Inclusion Criteria:

          -  Be willing and able to provide written informed consent for the trial.

          -  Be ≥ 18 years of age on day of signing informed consent.

          -  Have measurable disease based on RECIST 1.1.

          -  In dose escalation (Phase I), patients must have histologically or cytologically
             confirmed metastatic disease from any solid tumor that is incurable and fulfills one
             of the following criteria:

               -  Has demonstrated progression of disease following at least one line of effective
                  systemic therapy. Prior treatment with anti-CTLA-4 antibody (including
                  ipilimumab) is allowable OR

               -  For which effective therapy does not exist

          -  In dose expansion (part 2), patients must have histologically or cytologically
             confirmed unresectable or metastatic melanoma, renal cell carcinoma, ovarian cancer,
             or colorectal cancer.

          -  Renal cell patients must have had at least one prior VEGF TKI.

          -  Ovarian cancer patients must be resistant to platinum therapy (i.e. within 6 months of
             last platinum therapy).

          -  Patients with colorectal cancer should have progressed on at least one fluorouracil
             plus irinotecan or oxaliplatin containing regimen.

          -  Patients with melanoma should have unresectable or metastatic disease. Melanoma
             patients with BRAF V600E or V600K mutation-positive melanoma who have previously
             received a BRAF inhibitor with or without a MEK inhibitor) are eligible.

          -  In the dose expansion cohort patients should be willing to provide tissue from a newly
             obtained core or excisional biopsy of a tumor lesion (pre-treatment) and
             post-treatment biopsy. Newly-obtained is defined as a specimen obtained up to 6 weeks
             (42 days) prior to initiation of treatment on Day 1. Patients for whom newly-obtained
             samples cannot be provided (e.g., inaccessible, subject safety concern, or unwilling
             to undergo biopsy) may submit an archived specimen only upon agreement from the
             Sponsor. An on-treatment biopsy will be collected approximately halfway through the
             induction period, about 6 weeks from the start of study treatment (sometime between
             Cycle 2 Day 8 - Cycle 3 Day 1).

          -  Have a performance status of 0 or 1 on the ECOG Performance Scale (see Appendix A) up
             to 28 days before treatment initiation

          -  Demonstrate adequate organ function as defined in Table 1, all screening labs should
             be performed up to 28 days before treatment initiation.

          -  System Laboratory Value

          -  Hematological

               -  Absolute neutrophil count (ANC) ≥1,500 /mcL

               -  Platelets ≥100,000 / mcL

               -  Hemoglobin ≥9 g/dL or ≥5.6 mmol/L without transfusion or EPO dependency (within 7
                  days of assessment)

          -  Renal

             --Serum creatinine OR Measured or ≤1.5 X upper limit of normal (ULN) OR calculateda
             creatinine clearance ≥60 mL/min for subject with creatinine levels (GFR can also be
             used in place of > 1.5 X institutional ULN creatinine or CrCl)

          -  Hepatic

               -  Serum total bilirubin ≤ 1.5 X ULN OR Direct bilirubin ≤ ULN for subjects with
                  total bilirubin levels > 1.5 ULN AST (SGOT) and ALT (SGPT) ≤ 2.5 X ULN OR ≤ 5 X
                  ULN for subjects with liver metastases

               -  Albumin >2.5 mg/dL

          -  Coagulation

               -  International Normalized Ratio (INR) ≤1.5 X ULN unless subject is receiving
                  therapy as or Prothrombin Time (PT) long as PT or PTT is within therapeutic range
                  of intended use of anticoagulants

               -  Activated Partial Thromboplastin Time ≤1.5 X ULN unless subject is receiving
                  (aPTT) anticoagulant therapy as long as PT or PTT is within therapeutic range of
                  intended use of anticoagulants

          -  Creatinine clearance should be calculated per institutional standard.

          -  Negative protein on screening urinalysis

          -  Female subject of childbearing potential should have a negative serum pregnancy test
             within 24 hours prior to receiving the first dose of study medication.

          -  Female subjects of childbearing potential (Section 5.11.2) must be willing to use an
             adequate method of contraception as outlined in Section 5.11.2 - Contraception, for
             the course of the study through 120 days after the last dose of study medication.
             Should a woman become pregnant or suspect she is pregnant while she is participating
             in this study, she should inform her treating physician immediately.

          -  Abstinence is acceptable if this is the usual lifestyle and preferred contraception

          -  Male subjects of reproductive potential (Section 5.11.2) must agree to use an adequate
             method of contraception as outlined in Section 5.11.2- Contraception, starting with
             the first dose of study therapy through 120 days after the last dose of study therapy.

          -  Abstinence is acceptable if this is the usual lifestyle and preferred contraception
             for the subject.

        Exclusion Criteria:

          -  Is currently participating and receiving study therapy or has participated in a study
             of an investigational agent and received study therapy or used an investigational
             device within 4 weeks of the first dose of treatment.

          -  Has a diagnosis of immunodeficiency including subjects infected with Human
             Immunodeficiency Virus (HIV).

          -  Is receiving systemic steroid therapy or any other form of immunosuppressive therapy
             within 7 days prior to the first dose of trial treatment.

          -  Has a known history of active TB (Bacillus Tuberculosis).

          -  Has had a prior anti-cancer monoclonal antibody (mAb) within 4 weeks prior to study
             Day 1 or who has not recovered (i.e., ≤ Grade 1 or at baseline) from adverse events
             due to agents administered more than 4 weeks earlier.

          -  Has had prior chemotherapy, targeted small molecule therapy, or radiation therapy
             within 2 weeks prior to study Day 1 or who has not recovered (i.e., ≤ Grade 1 or at
             baseline) from adverse events due to a previously administered agent.

          -  Subjects with ≤ Grade 2 neuropathy are an exception to this criterion and may qualify
             for the study.

          -  If subject received major surgery, they must have recovered adequately from the
             toxicity and/or complications from the intervention prior to starting therapy.

          -  Has a known additional malignancy that is progressing or requires active treatment.
             -Exceptions include basal cell carcinoma of the skin or squamous cell carcinoma of the
             skin that has undergone potentially curative therapy or in situ cervical cancer.

          -  Lesions suspected to be at higher-risk for bleeding such as bowel involvement with
             tumor that invades into the bowel wall or involves the intraluminal component of bowel
             by imaging or direct visualization or central pulmonary lesions.

          -  Ulcerated skin lesions

          -  Poorly-controlled hypertension as defined BP > 150/100 mmHg, or SBP > 180 mmHg when
             DBP < 90 mmHg, on at least 2 repeated determinations on separate days within 3 months
             prior to study enrollment.

          -  History within 6 months prior to treatment of myocardial infarction, severe/unstable
             angina pectoris, CABG, NYHA class III or IV CHF, stroke or TIA.

          -  History within 3 months prior to treatment of Grade 3-4 GI bleeding/hemorrhage,
             treatment resistant peptic ulcer disease, erosive esophagitis or gastritis, infectious
             or inflammatory bowel disease, diverticulitis, pulmonary embolus, or other
             uncontrolled thromboembolic event.

          -  Patients who are less than 4 weeks post-op after major surgery.

          -  History of allergic reactions attributed to compounds of similar chemical or biologic
             composition to pembrolizumab and trebananib including history of allergic reactions to
             bacterially produced proteins.

          -  Has known active central nervous system (CNS) metastases and/or carcinomatous
             meningitis. Subjects with previously treated brain metastases may participate provided
             they are stable (without evidence of progression by imaging for at least four weeks
             prior to the first dose of trial treatment and any neurologic symptoms have returned
             to baseline), have no evidence of new or enlarging brain metastases, and are not using
             steroids for at least 7 days prior to trial treatment. This exception does not include
             carcinomatous meningitis which is excluded regardless of clinical stability.

          -  Has active autoimmune disease that has required systemic treatment in the past 2 years
             (i.e. with use of disease modifying agents, corticosteroids or immunosuppressive
             drugs). Replacement therapy (eg., thyroxine, insulin, or physiologic corticosteroid
             replacement therapy for adrenal or pituitary insufficiency, etc.) is not considered a
             form of systemic treatment.

          -  Treatment within 30 days prior to enrollment/randomization with strong immune
             modulators including but not limited to systemic cyclosporine, tacrolimus, sirolimus,
             mycophenolate mofetil, methotrexate, azathioprine, rapamycin, thalidomide, and
             lenalidomide.

          -  Uncontrolled intercurrent illness including, but not limited to, ongoing or active
             infection, interstitial lung disease or active, non-infectious pneumonitis, nephritis,
             pancreatitis, symptomatic congestive heart failure, unstable angina pectoris, cardiac
             arrhythmia, or psychiatric illness/social situations that would limit compliance with
             study requirements.

          -  Has a history of (non-infectious) pneumonitis that required steroids or current
             pneumonitis.

          -  Has an active infection requiring systemic therapy.

          -  Has a history or current evidence of any condition, therapy, or laboratory abnormality
             that might confound the results of the trial, interfere with the subject's
             participation for the full duration of the trial, or is not in the best interest of
             the subject to participate, in the opinion of the treating investigator.

          -  Has known psychiatric or substance abuse disorders that would interfere with
             cooperation with the requirements of the trial.

          -  Is pregnant or breastfeeding, or expecting to conceive or father children within the
             projected duration of the trial, starting with the pre-screening or screening visit
             through 120 days after the last dose of trial treatment.

          -  Patient with ovarian cancer and colorectal cancer who have received prior therapy with
             an anti-PD-1, anti-PD-L1, or anti-PD-L2 antibody. Melanoma and renal cell carcinoma
             patients who received prior anti-PD-1 or ant-PD-L1 or CTLA-4 antibodies are allowed to
             participate.

          -  Has received trebananib or another angiopoietin-2 directed therapy (prior treatment
             with bevacizumab is not an exclusion criteria)

          -  Has active Hepatitis B (e.g., HBsAg reactive) or Hepatitis C (e.g., HCV RNA
             [qualitative] is detected).

          -  Has received a live vaccine within 30 days of planned start of study therapy.