Study of BMS-986205 and Nivolumab in Endometrial Cancer or Endometrial Carcinosarcoma That Has Not Responded to Treatment

Inclusion Criteria: * Subjects must have recurrent or persistent endometrial carcinoma (including: Endometrioid adenocarcinoma, serous adenocarcinoma, undifferentiated carcinoma, dedifferentiated carcinoma, clear cell adenocarcinoma, mixed epithelial carcinoma, adenocarcinoma not otherwise specified (N.O.S.), mucinous adenocarcinoma, squamous cell carcinoma, and transitional cell carcinoma) or endometrial carcinosarcoma). Histologic documentation of diagnosis of carcinoma is required. * All patients must have measurable disease. Measurable disease is defined by RECIST (version 1.1). Measurable disease is defined as at least one lesion that can be accurately measured in at least one dimension (longest diameter to be recorded). Each lesion must be ≥ 10 mm when measured by CT, MRI or caliper measurement by clinical exam; or ≥ 20 mm when measured by chest x-ray. Lymph nodes must be ≥ 15 mm in short axis when measured by CT or MRI. * Patients must have at least one "target lesion" to be used to assess response on this protocol as defined by RECIST version 1.1 (Section 12.0). Tumors within a previously irradiated field will be designated as "non-target" lesions unless progression is documented, or a biopsy is obtained to confirm persistence at least 90 days following completion of radiation therapy. * Females, age ≥ 18 years and life expectancy of ≥ 12 weeks. * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. * Resolution of (non-laboratory) adverse effects …