Inclusion Criteria:

          -  Diagnosis of metastatic or locally advanced and unresectable high-grade soft tissue
             sarcoma. Unresectable is defined as:

               1. primary tumor cannot be safely removed surgically, or

               2. primary tumor would benefit from systemic therapy prior to a surgical approach

          -  Be willing and able to provide written informed consent

          -  Must consent to mandatory tumor biopsy (if deemed safe and feasible) for research
             studies at screening, if archival tissue is not available, and at C1D15, C3D15.

          -  Age ≥ 18 years

          -  ECOG performance status ≤ 1

          -  Presence of measurable disease per RECIST v1.1

               -  Target lesions must not be chosen from a previously irradiated field unless there
                  has been radiographically and/or pathologically documented tumor progression in
                  that lesion prior to enrollment.

          -  No prior systemic therapy (see exclusion criteria, below)

          -  Negative serum pregnancy test in women of childbearing potential

          -  Patients with chronic HBV (HBsAg-positive with undetectable or low HBV DNA and normal
             ALT, or HBsAg-negative with anti-HBc-positive serology) and HCV (completed curative
             antiviral treatment with HCV viral load below the limit of quantification) may be
             eligible

               -  Patients with HBV should be treated with suppressive antiviral therapy prior to
                  enrollment

               -  Patients with HCV must have completed curative therapy and have negative HCV
                  viral load

          -  Adequate organ function, as defined in Table 2:

        Table 2: Laboratory Parameters Required for Study Inclusion

        Hematological Absolute neutrophil count (ANC): ≥ 1,500 /mcL Platelets: ≥ 75,000 / mcL
        Hemoglobin: ≥ 9g/dL or ≥ 5.6 mmol/L

        Renal Serum creatinine: ≤ 1.5 X upper limit of normal (ULN) OR Measured or calculated
        creatinine clearance: ≥ 60 mL/min for patient with creatinine levels > 1.5 X institutional
        ULN (GFR can also be used in place of creatinine orCrCl)

        Hepatic Serum total bilirubin: ≤ 1.5 X ULN OR Direct bilirubin ≤ ULN for patients with
        total bilirubin levels > 1.5 ULN except patients with Gilbert's disease (≤ 3x ULN) AST
        (SGOT) and ALT (SGPT): ≤ 2.5 X ULN OR ≤ 5 X ULN for patients with liver metastases

        Exclusion Criteria:

          -  Received any systemic therapy in the advanced or metastatic setting

               -  Adjuvant or neoadjuvant therapies received ≥ 1 year prior to enrollment are
                  permitted

          -  Unstable or deteriorating cardiovascular disease within the previous 6 months,
             including:

               -  Unstable angina or myocardial infarction

               -  CVA/stroke

               -  New York Heart Association [NYHA] Class III or IV congestive heart failure

               -  Uncontrolled clinically significant arrhythmias

          -  Current use of immunosuppressive medication, EXCEPT for the following:

               -  Intranasal, inhaled, topical steroids, or local steroid injection (e.g.,
                  intra-articular injection)

               -  Systemic corticosteroids at physiologic doses ≤ 10 mg/day of prednisone or
                  equivalent

               -  Steroids as premedication for hypersensitivity reactions (e.g., CT scan
                  premedication)

          -  Evidence of clinically significant immunosuppression such as the following:

               -  Primary immunodeficiency state such as Severe Combined Immunodeficiency Disease

               -  Concurrent opportunistic infection

               -  Receiving systemic immunosuppressive therapy (> 2 weeks) including oral steroid
                  doses > 10 mg/day of prednisone or equivalent within 2 months prior to enrollment

          -  History or evidence of symptomatic autoimmune disease in past 2 years prior to
             enrollment.

               -  Replacement therapy (e.g., thyroxine for hypothyroidism, insulin for diabetes or
                  physiologic corticosteroid replacement therapy for adrenal or pituitary
                  insufficiency) is not considered a form of systemic treatment for autoimmune
                  disease

          -  Uncontrolled HIV infection, as defined by one or more of the following:

               -  Patients with CD4+ T-cell (CD4+) counts < 350 cells/uL

               -  Patients with a history of an opportunistic infection secondary to AIDS

               -  Patients on anti-microbials with drug-drug interactions with the study drugs on
                  this protocol, who cannot be switched to alternative anti-microbials

               -  Patients on antiretroviral therapy < 4 weeks

               -  Patients with HIV viral load > 400 copies/mL

          -  Active Hepatitis B or Hepatitis C

          -  Patients who have received a live vaccine within 30 days of the start date of the
             planned study therapy (with the exception of COVID-19 vaccines)

          -  History of active TB (Bacillus Tuberculosis)

          -  Radiation therapy within 2 weeks prior to study day 1

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

          -  Women who are pregnant or breast feeding

          -  Patients expecting to conceive or father children within the projected duration of the
             trial, starting with the visit through 180 days after the last dose of study
             treatment(s)

          -  Prior organ transplantation including allogenic stem-cell transplantation

          -  Active infection requiring systemic therapy

          -  Known prior severe hypersensitivity to investigational product or any component in its
             formulations, including known severe hypersensitivity reactions to monoclonal
             antibodies (NCI CTCAE v5.0 Grade ≥ 3)

          -  Patients with prior history of interstitial lung disease and clinically significant
             pulmonary compromise, including those who have a requirement for supplemental oxygen
             use to maintain adequate oxygenation