Inclusion Criteria:

          -  Individuals must meet all of the inclusion criteria in order to be eligible to
             participate in the study, as follows:

               -  Male or Female ≥ 18 years of age

               -  Pathologically confirmed diagnosis of locally advanced unresectable or metastatic
                  soft tissue sarcoma

               -  For the Phase 1 Part of Study, only previously treated patients will be enrolled.
                  For the Phase 2 Part of Study, previously untreated patients will be enrolled.

               -  Ability to understand the purposes and risks of the study and has signed and
                  dated a written informed consent form approved by the investigator's IRB/Ethics
                  Committee

               -  Willingness to comply with all study procedures and availability for the duration
                  of the study.

               -  Measurable disease by RECIST v1.1

               -  ECOG performance status ≤1

               -  Life expectancy of at least 3 months

               -  Acceptable liver function: Bilirubin ≤ 1.5 times upper limit of normal (ULN;
                  except subjects with Gilbert Syndrome who must have a total bilirubin level ≤ 3.0
                  ULN);AST (SGOT), ALT (SGPT) and alkaline phosphatase ≤ 3 x ULN (≤ 5 x ULN if
                  liver metastases)

               -  Acceptable renal function: Creatinine ≤1.5 times ULN or ≥ 60 mL/min (using the
                  Cockcroft Gault formula)

               -  Acceptable hematologic status (without hematologic support): WBC ≥2000/µL; ANC ≥
                  1500 cells/μL; Platelet count ≥ 100,000/μL; Hemoglobin ≥ 9.0 g/dL; Normal PT,
                  PTT, INR

               -  All women of childbearing potential must have a negative pregnancy test and all
                  subjects must agree to use highly effective means of contraception (surgical
                  sterilization or the use of barrier contraception with either a condom or
                  diaphragm in conjunction with spermicidal gel or an IUD) with their partner from
                  entry into the study through 5 months for women and 7 months for men after the
                  last dose.

        Exclusion Criteria:

          -  All individuals meeting any of the exclusion criteria at baseline will be excluded
             from study participation, as follows:

               -  Prior treatment with an anti-PD-1, anti-PD-L1, anti-PD-L2, anti-CTLA4 antibody,
                  or any other antibody or drug specifically targeting T-cell co-stimulation or
                  checkpoint pathways

               -  Subjects with untreated CNS metastases. Subjects are eligible if CNS metastases
                  have been adequately treated and have neurologically returned to baseline (except
                  for residual signs or symptoms related to the CNS treatment) for at least 2 weeks
                  prior to treatment initiation. In addition, subjects must be either off
                  corticosteroids, or on a stable or decreasing dose of ≤10 mg daily prednisone (or
                  equivalent) for at least 2 weeks prior to treatment initiation.

               -  Subjects with carcinomatous meningitis

               -  Anticancer treatment with radiation therapy, chemotherapy, targeted therapy or
                  other antitumor treatment within 2 weeks prior to study entry

               -  Subjects who participated in an investigational drug or device study within 14
                  days prior to study entry

               -  Females who are pregnant or breast-feeding

               -  Unwillingness or inability to comply with the study protocol for any reason

               -  Concurrent or prior immunotherapy with anti-CTLA4 or anti-PD-1 inhibitors

               -  Non-oncology vaccine therapy used for prevention of infectious disease within 4
                  weeks of trial enrollment

               -  Autoimmune disease including rheumatoid arthritis, systemic progressive sclerosis
                  (scleroderma), systemic lupus erythematosus, autoimmune vasculitis and motor
                  neuropathy considered to be of autoimmune origin (e.g. Guillain-Barre Syndrome)

               -  Systemic immunosuppression, including HIV positive status with or without AIDS

               -  Skin rash (psoriasis, eczema) affecting ≥ 25% body surface area

               -  Inflammatory bowel disease (Crohn's or ulcerative colitis)

               -  Ongoing or uncontrolled diarrhea within 4 weeks of trial enrollment

               -  Recent history of acute diverticulitis, intraabdominal abscess or
                  gastrointestinal obstruction within 6 months of trial enrollment, which are known
                  risk factors for bowel perforation

               -  Patients with congestive heart failure or recent cardiac event

               -  Evidence of severe or uncontrolled systemic disease or any other concurrent
                  condition, including psychiatric, which in the principal investigator's opinion
                  makes it undesirable for the patient to participate in the trial or which would
                  jeopardize compliance with the trial

               -  Any positive test for hepatitis B virus or hepatitis C virus indicating acute or
                  chronic infection

               -  Known history of testing positive for human immunodeficiency virus (HIV) or known
                  acquired immunodeficiency syndrome (AIDS).

               -  Inadequate hematologic, renal or hepatic function defined by any of the following
                  screening laboratory values: WBC ≤2000/µL; Neutrophils ≤1500/µL; Platelets ≤
                  100,000/µL; hemoglobin ≤9.0 g/dL; Serum creatinine ≥1.5 x ULN or creatinine
                  clearance ≤ 60 mL/min (using the Cockcroft Gault formula); AST/ALT ≥3 x ULN (≥ 5
                  x ULN if liver metastases); Total Bilirubin ≥1.5 x ULN (except subjects with
                  Gilbert Syndrome who must have a total bilirubin level ≥ 3.0 ULN)

               -  Current, active or previous history of heavy alcohol abuse

               -  Pituitary endocrinopathy

               -  Adrenal insufficiency or excess