Study of Nivolumab With or Without Pazopanib in Metastatic or Unresectable Soft Tissue Sarcomas

Inclusion Criteria:

* Histologic diagnosis of metastatic or unresectable soft tissue or bone sarcoma
* No prior therapy with nivolumab in either cohorts or with pazopanib in the combination cohort
* At least one line of systemic therapy or ineligibility for an anthracycline based chemotherapy
* At least 2 distinct measurable metastatic sites
* Adequate organ and marrow function as defined by initial laboratory tests
* Life expectancy \> 3 months
* Stable brain metastases for at least 4 weeks and no steroid dependence

Exclusion Criteria:

* Autoimmune disease Any underlying medical or psychiatric condition, which in the opinion of the Investigator, will make the administration of study drugs hazardous or obscure the interpretation of adverse events
* Concomitant therapy with any non-study immunotherapy regimens, cytotoxic chemotherapy, immunosuppressive agents, other investigation therapies Chronic use of systemic corticosteroids greater than prednisone 10 mg daily or its equivalent
* Women of childbearing potential who are unwilling or unable to use an acceptable method to avoid pregnancy for the entire study period and for at least 5 months after cessation of study drug, or have a positive pregnancy test at baseline, or are pregnant or breastfeeding;
* Prisoners or subjects who are compulsorily detained (involuntarily incarcerated) for treatment of either a psychiatric or physical illness.