Inclusion Criteria (abbreviated):

          -  Documented adenocarcinoma of the pancreas

          -  Have disease progression after prior chemotherapy for metastatic pancreas cancer (or
             adjuvant or neoadjuvant if progression occurred within 6 months of completing this
             regimen)

          -  Presence of at least one measurable lesion

          -  Patient acceptance to have a tumor biopsy of an accessible lesion at 2 time points
             (baseline and on study)

          -  ECOG performance status of 0 or 1

          -  Life expectancy of greater than 3 months

          -  Adequate organ and marrow function defined by study-specified laboratory tests

        Exclusion Criteria (abbreviated):

          -  Brain metastases

          -  Clinical or radiographic ascites (some trace amount may be allowed)

          -  Rapidly progressing disease

          -  Live vaccine within 30 days of study treatment (flu vaccine allowed)

          -  Surgery within 28 days of study treatment (some exceptions for minor procedures)

          -  Use of an investigational agent or device within 28 days of study treatment.

          -  Chemotherapy, radiation, or biological cancer therapy within 14 days of study
             treatment.

          -  Prior treatment with anti-CTLA-4, anti-PD-1, anti-PD-L1, or anti PD-L2, or with IDO
             inhibitor.

          -  Use of growth factors within 14 days of study treatment

          -  Use of any systemic steroids within 14 days of study treatment or other
             immunosuppressive agents within 7 days of study treatment.

          -  Use of more than 2 g/day of acetaminophen

          -  Use of any UGT1A9 inhibitor

          -  Use of warfarin

          -  Use of MAOIs or drugs with significant MAOI activity within the 21 days of screening

          -  History of Seratonin Syndome

          -  Known allergy to both penicillin and sulfa

          -  Known or suspected hypersensitivity to any monoclonal antibody or any study drug
             component

          -  Have artificial joints or implants that cannot be easily removed or a history of
             infection associated with an implant

          -  Significant or malignant pleural effusion

          -  New pulmonary embolism, extremity deep venous thromboembolism, or portal vein
             thrombosis within 2 months of study enrollment

          -  History of autoimmune disease (exceptions for Graves or Hashimoto's disease, vitiligo,
             and type I diabetes mellitus)

          -  Gastrointestinal condition that may affect drug absorption

          -  Significant heart disease or heart disease requiring antibiotic for prevention of
             endocarditis

          -  History of abnormal electrocardiogram (ECG) that is deemed meaningful by the
             investigator

          -  History of (non-infectious) pneumonitis that required steroids, evidence of
             interstitial lung disease or active, non-infectious pneumonitis

          -  Pulse oximetry of < 92% on room air or the need for supplemental home oxygen

          -  Infection with HIV, hepatitis B or hepatitis C

          -  Other conditions, including alcohol or drug dependence, intercurrent illness, or lack
             of sufficient peripheral venous access that would affect the patient's ability to
             comply with study visits and procedures

          -  Pregnant or breastfeeding women

          -  Unwillingness or inability to follow the study schedule for any reason