Inclusion:

          1. Histopathologic documentation of pancreatic adenocarcinoma, colorectal adenocarcinoma,
             cholangiocarcinoma, esophageal cancer and gastric cancer with radiographic evidence of
             metastatic disease.

          2. Male or female subjects greater than or equal to 18 years of age.

          3. ECOG/ Zubrod performance status of 0 or 1.

          4. Women of childbearing potential (WOCBP) must be using an adequate method of
             contraception to avoid pregnancy throughout the study in such a manner that the risk
             of pregnancy is minimized. Suggested precautions should be used to minimize the risk
             or pregnancy for at least 1 month before start of therapy, and while women are on
             study for at least 8 weeks after pembrolizumab is stopped. WOCBP include any female
             who has experienced menarche and who has not undergone successful surgical
             sterilization (hysterectomy, bilateral tubal ligation or bilateral oophorectomy) or is
             not postmenopausal. Acceptable forms of birth control include condom, diaphragm,
             hormonal, IUD, or sponge plus spermacide. Abstinence is also an acceptable form of
             birth control.

          5. Men must be willing and able to use an acceptable method of birth control, during and
             for at least 3 months after completion of the study, if their sexual partners are
             WOCBP.

          6. Willing and able to give informed consent.

          7. Adequate vein access: consider PICC or other central line.

          8. Patients must have adequate tissue (fresh or frozen) available or planned removal of
             adequate tissue for analysis. At least 250mg of tumor are needed for peptide elution.
             There is no specific time limit on how long the tissue can remain frozen prior to use.
             The tissue will be collected and analyzed under Lab protocol PA15-0176.

          9. Patients can have any lines (including zero) of prior therapy to sign consent prior to
             tissue harvest.

         10. Toxicity related to prior therapy must either have returned to </= grade 1, baseline,
             or been deemed irreversible.

         11. ELIGIBILITY FOR TREATMENT: ECOG/Zubrod performance status of 0 to 2.

         12. Bi-dimensionally measurable disease by radiographic imaging (CT scan) that represents
             at least one measurable lesion per RECIST v1.1.

         13. At least 4 Weeks must have elapsed since the last chemotherapy, radiotherapy or major
             surgery.

         14. Toxicity related to prior therapy must either have returned to less than or equal to
             grade 1, baseline, or been deemed irreversible.

         15. Subjects must have received at least one line of chemotherapy prior to receiving
             adoptive T cell therapy and should have exhausted standard of care systemic therapy
             options. The decision to implement the T cell therapy will be at the discretion of the
             treating physician. The timing and total exposure to chemotherapy will depend on the
             tumor type in question (more systemic options for breast cancer; fewer for gastric
             cancer, for example). Due to the heterogeneity of tumors being treated in this
             protocol, the discretion of the treating physician in terms of timing of immunotherapy
             will be critical.

        Exclusion:

          1. EXCLUSION FOR ENROLLMENT: Any other malignancy from which the patient has been
             disease-free for less than 5 years, with the exception of adequately treated and cured
             basal or squamous cell skin cancer, superficial bladder cancer, and carcinoma in situ
             of the cervix.

          2. Pregnant women, nursing mothers, men or women of reproductive ability who are
             unwilling to use effective contraception. Women of childbearing potential with a
             positive pregnancy test within 3 days prior to entry.

          3. Significant cardiovascular abnormalities as defined by any one of the following: 1.
             Congestive heart failure NYHA classes II-IV. Patients with asymptomatic class I CHF
             may participate in conjunction with a Cardiology consultation. 2. Clinically
             significant hypotension. 3. Symptoms of coronary artery disease. 4. Presence of
             arrhythmias in EKG requiring drug therapy.

          4. Active and untreated central nervous system (CNS) metastases (including metastasis
             identified during screening MRI or contrast CT). Patients with asymptomatic, treated
             metastases may be eligible if their lesion(s) have demonstrated stability over 2
             months.

          5. Autoimmune disease: Patients with a history of Inflammatory Bowel Disease are excluded
             from this study, as are patients with a history of autoimmune disease (e.g. Systemic
             Lupus Erythematosus, vasculitis, infiltrating lung disease) whose possible progression
             during treatment would be considered by the Investigator to be unacceptable.

          6. Any underlying medical or psychiatric condition, which in the opinion of the
             Investigator, will make the administration of study drug hazardous or obscure the
             interpretation of adverse events, such as a condition associated with frequent
             diarrhea.

          7. Inadequate organ function at enrollment defined by: WBC less than or equal to 2000/uL.
             Hct less than or equal to 24% or Hgb less than or equal to 8 g/dL. ANC less than or
             equal to 1000. Platelets less than or equal to 75,000. Creatinine greater than or
             equal to 1.5 x ULN OR creatinine clearance >50 ml/min/1.73m2 for patients with
             creatinine levels above institutional normal limits. AST/ALT greater than or equal to
             2.5 x ULN. Bilirubin greater than or equal to 2.0 x ULN

          8. Positive screening tests for HIV, Hep B, and Hep C. If positive results are not
             indicative of true active or chronic infection, the patient can be treated

          9. EXCLUSION CRITERIA FOR TREATMENT: WBC less than or equal to 2000/uL. Hct less than or
             equal to 24% or Hgb less than or equal to 8 g/dL. ANC less than or equal to 1000.
             Platelets less than or equal to 75,000. Creatinine greater than or equal to 1.5 x ULN
             OR creatinine clearance >50 ml/min/1.73m2 for patients with creatinine levels above
             institutional normal limits. AST/ALT greater than or equal to 2.5 x ULN. Bilirubin
             greater than or equal to 2.0 x ULN

         10. Pregnant women, nursing mothers, men or women of reproductive ability who are
             unwilling to use effective contraception. Women of childbearing potential with a
             positive pregnancy test within 3 days prior to entry.

         11. Steroids are not permitted 3 days prior to T cell infusion and concurrently during
             therapy.

         12. Uncontrolled concurrent illness including, but not limited to ongoing or active
             infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac
             arrhythmia, or psychiatric illness/social situations that would limit compliance with
             study requirements.

         13. Any non-oncology vaccine therapy used for the prevention of infectious disease within
             1 month before or after any anti-PD-1 dose.

         14. After the T cell infusion, patients may not be on any other treatments for their
             cancer aside from those included in the treatment section of the protocol.

         15. Coagulation ≤1.5 x ULN unless participant is receiving anticoagulant therapy as long
             as PT or a PTT is within therapeutic range of intended use of anticoagulants.