Inclusion Criteria:

          1. Written informed consent must be obtained prior to any procedures.

          2. Male or female patient aged 18 years or older.

          3. Pathologic diagnosis of solid tumor malignancy that is locally advanced or metastatic
             at time of Screening:

             Part 1 Dose escalation camidanlumab tesirine as monotherapy:

             Selected advanced solid tumors: colorectal, head and neck, NSCLC, gastric and
             esophageal cancers, pancreas, bladder, renal cell carcinoma, melanoma, TNBC, and
             ovarian/fallopian tube cancers

             Part 1 Dose-escalation camidanlumab tesirine in combination with pembrolizumab:

             Selected advanced solid tumors: colorectal cancer, gastric-esophageal cancer, ovarian
             /fallopian tube cancer, pancreatic cancer, non-small cell lung cancer, and melanoma.

             Note: For colorectal cancer, gastric-esophageal cancer, ovarian/fallopian tube cancer,
             pancreatic cancers mismatch repair (MMR) / microsatellite stability (MSS) /
             microsatellite instability (MSI) status is mandatory. If MMR/MSS/MSI status is not
             available at signature of the informed consent, the test should be performed before
             Cycle 1 Day 1 (C1D1).

             Part 2 Dose expansion camidanlumab tesirine in combination with pembrolizumab:

               -  Group 1: One of the indications identified in Part 1, for which at least 1
                  response (PR or CR) was seen.

               -  Group 2: Selected advanced solid tumors: colorectal cancer, gastric-esophageal
                  cancer, ovarian/fallopian tube cancer, pancreatic cancer, non-small cell lung
                  cancer, melanoma, with the exception for the one selected for Group 1.

             Note: For colorectal cancer, gastric-esophageal cancer, ovarian/fallopian tube cancer,
             pancreatic cancers MMR/MSS/MSI status is mandatory. If MMR/MSS/MSI status is not
             available at signature of the informed consent, the test should be performed before
             C1D1.

          4. Patients who are refractory to or intolerant of existing therapy(ies) known to provide
             clinical benefit for their condition.

          5. Patients with advanced/metastatic cancer, with measurable disease as determined by
             RECIST v1.1 or immune-related Response Criteria (irRC)/ immune-related Response
             Evaluation Criteria In Solid Tumors (irRECIST)/ immune-related Response Evaluation
             Criteria In Solid Tumors (iRECIST)/ immune-modified Response Evaluation Criteria in
             Solid Tumors (imRECIST) as per Investigator discretion.

          6. A) For camidanlumab tesirine as monotherapy: Patient must have a site of disease
             amenable to biopsy and be willing to undergo fresh biopsy procedures (minimum 3 passes
             each) prior to first dose, according to the treating institution's guidelines.

             B) Patients included in the paired-biopsy cohort must in addition be willing to
             undergo fresh biopsy procedures (minimum 3 passes each) after receiving at least 1
             dose of study drug.

             C) For camidanlumab tesirine in combination with pembrolizumab: Patient must have a
             site of disease amenable to biopsy and must provide fresh tumor biopsy prior to C1D1,
             and be willing to undergo fresh biopsy procedures (minimum 3 passes each) after
             receiving at least 1 dose of study treatment, according to the treating institution's
             guidelines.

          7. ECOG performance status 0-1.

          8. Patient with life expectancy ≥ 3 months as per Investigator assessment.

          9. Adequate organ function as defined by screening laboratory values within the following
             parameters:

               1. Absolute neutrophil count (ANC) ≥ 1.5 × 10^3/μL (off growth factors at least 72
                  hours).

               2. Platelet count ≥100 × 10^3/μL without transfusion in the past 10 days.

               3. Hemoglobin ≥9 g/dL (5.6 mmol/L) (prior transfusion allowed).

               4. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), or gamma
                  glutamyl transferase (GGT) ≤2.5 × the upper limit of normal (ULN) if there is no
                  liver involvement; ALT or AST ≤5 × ULN if there is liver involvement.

               5. Total bilirubin ≤1.5 × ULN (patients with known Gilbert's syndrome may have a
                  total bilirubin up to ≤3 × ULN with direct bilirubin ≤1.5 × ULN).

               6. Blood creatinine ≤1.5 × ULN or calculated creatinine clearance ≥60 mL/min by the
                  Cockcroft-Gault equation.

         10. Negative beta-human chorionic gonadotropin (β-HCG) pregnancy test within 7 days prior
             to start of study drug for women of childbearing potential (WOCBP).

         11. Women of childbearing potential must agree to use a highly effective method of
             contraception from the time of giving informed consent until at least 6.5 months after
             the last dose of camidanlumab tesirine or 4 months after last dose of pembrolizumab,
             whichever is the latest. Men with female partners who are of childbearing potential
             must agree to use a condom when sexually active or practice total abstinence from the
             time of giving informed consent until at least 16 weeks after the patient receives his
             last dose of camidanlumab tesirine or 4 months after last dose of pembrolizumab,
             whichever is the latest.

        Exclusion Criteria:

          1. Participation in another investigational interventional study.

          2. Prior therapy with a CD25 (IL-2R) antibody within the last 4 months.

          3. Known history of ≥Grade 3 hypersensitivity to a therapeutic antibody.

          4. Patients with prior solid organ or allogeneic bone marrow transplant.

          5. History of symptomatic autoimmune disease (e.g., rheumatoid arthritis, systemic
             progressive sclerosis [scleroderma], systemic lupus erythematosus, Sjögren's syndrome,
             autoimmune vasculitis [e.g., Wegener's granulomatosis]) (patients with vitiligo, type
             1 diabetes mellitus, residual hypothyroidism, hypophysitis due to autoimmune condition
             only requiring hormone replacement may be enrolled).

          6. History of neuropathy considered of autoimmune origin (e.g., polyradiculopathy
             including Guillain-Barré syndrome and myasthenia gravis) or other central nervous
             system (CNS) autoimmune disease (e.g., poliomyelitis, multiple sclerosis).

          7. History of recent infection (within 4 weeks of C1D1) caused by a pathogen known to be
             associated with GBS, for example: herpes simplex virus 1/2 (HSV1, HSV2), varicella
             zoster virus (VZV), Epstein-Barr virus (EBV), cytomegalovirus (CMV), measles,
             Influenza A, Zika virus, Chikungunya virus, mycoplasma pneumonia, Campylobacter
             jejuni, enterovirus D68, or severe acute respiratory syndrome coronavirus 2
             (SARS-CoV-2).

             Note: An influenza test and a pathogen-directed SARS-CoV-2 test (such as polymerase
             chain reaction [PCR]) are mandatory and must be negative before initiating study
             treatment (tests to be performed 3 days or less prior to dosing on C1D1; an additional
             2 days are allowed in the event of logistical issues for receiving the results on
             time).

          8. Known seropositive and requiring anti-viral therapy for human immunodeficiency (HIV)
             virus, hepatitis B virus (HBV), or hepatitis C virus (HCV). Note: Testing is not
             mandatory to be eligible but should be considered in patients with high risk for these
             infections; testing is mandatory if status is unknown.

          9. History of Stevens-Johnson syndrome or toxic epidermal necrolysis.

         10. Failure to recover to ≤Grade 1 (Common Terminology Criteria for Adverse Events version
             4.0 [CTCAE version 4.0]) from acute nonhematologic toxicity (to ≤Grade 2 for
             neuropathy or alopecia), due to previous therapy, prior to screening.

         11. Symptomatic CNS metastases or evidence of leptomeningeal disease (brain MRI or
             previously documented cerebrospinal fluid [CSF] cytology). Previously treated
             asymptomatic CNS metastases are permitted provided that the last treatment (systemic
             anticancer therapy and/or local radiotherapy) was completed ≥4 weeks prior to Day 1
             except usage of low dose of steroids on a taper (i.e., up to 10 mg prednisone or
             equivalent on Day 1 and consecutive days is permissible if being tapered down).
             Patients with discrete dural metastases are eligible.

         12. Clinically significant third space fluid accumulation (i.e., ascites requiring
             drainage or pleural effusion that is either requiring drainage or associated with
             shortness of breath).

         13. Active diarrhea CTCAE Grade 2 or a medical condition associated with chronic diarrhea
             (such as irritable bowel syndrome, inflammatory bowel disease).

         14. Active infection requiring systemic antibiotic therapy.

         15. Active bleeding diathesis or significant anticoagulation (international normalized
             ratio [INR] ≥2.0).

         16. Breastfeeding or pregnant.

         17. Significant medical comorbidities, including uncontrolled hypertension (blood pressure
             [BP] ≥160 mmHg systolic and/or ≥110 mmHg diastolic repeatedly with or without anti
             hypertensive medication), unstable angina, congestive heart failure (greater than New
             York Heart Association class II), electrocardiographic evidence of acute ischemia,
             coronary angioplasty or myocardial infarction within 6 months prior to screening,
             severe uncontrolled atrial or ventricular cardiac arrhythmia, poorly controlled
             diabetes, active ulceration of the upper gastrointestinal (GI) tract or GI bleeding,
             or severe chronic pulmonary disease.

         18. Major surgery, radiotherapy, chemotherapy or other anti-neoplastic therapy within 14
             days prior to start of study drug (C1D1), except shorter if approved by the Sponsor.
             For cytotoxic agents that have major delayed toxicity, e.g., mitomycin C and
             nitrosoureas, 4 weeks is indicated as washout period. For patients receiving systemic
             anticancer immunotherapies (as opposed to intralesional) that lead to activation of
             Teffs and/or increase the Teff/Treg ratio, such as anti-PD-1 antibodies, 4 weeks are
             indicated as the washout period.

         19. Use of any other experimental medication within 14 days prior to start of study drug
             (C1D1).

         20. Patients requiring concomitant immunosuppressive agents or chronic treatment with
             corticosteroids except:

               -  replacement dose steroids in the setting of adrenal insufficiency

               -  topical, inhaled, nasal, and ophthalmic steroids are allowed.

         21. Planned live vaccine within 30 days prior to the first dose of study treatment and
             during study treatment.

         22. Congenital long QT syndrome, or a corrected QTcF interval of ≥ 480 ms, at screening
             (unless secondary to pacemaker or bundle branch block).

         23. Active second primary malignancy other than non-melanoma skin cancers, non-metastatic
             prostate cancer, in situ cervical cancer, ductal or lobular carcinoma in situ of the
             breast, or other malignancy that the Sponsor's medical monitor and Investigator agree
             and document should not be exclusionary.

         24. Any other significant medical illness, abnormality, or condition that would, in the
             Investigator's judgment, make the patient inappropriate for study participation or put
             the patient at risk.

         25. For patients treated with camidanlumab tesirine in combination with pembrolizumab:
             patients intolerant to checkpoint-inhibitor or with a history of the following ≥ Grade
             3 immune-related adverse events: hepatitis, renal, ocular, neurologic, cardiovascular,
             rheumatologic, and hematologic.

         26. For patient treated with camidanlumab tesirine in combination with pembrolizumab:
             patients with a history of non-infectious pneumonitis related to prior systemic
             treatment and that require treatment with steroids within the last 6 months prior to
             enrollment.