Safety and Efficacy of Retifanlimab (INCMGA00012) Alone or in Combination With Other Therapies in Participants With Advanced or Metastatic Endometrial Cancer Who Have Progressed on or After Platinum-based Chemotherapy.

Prior treatment

• Receipt of anticancer therapy within 28 days of the first administration of study treatment, with the exception of localized radiotherapy.
• Toxicity of prior therapy that has not recovered to ≤ Grade 1 or baseline unless approved by the medical monitor.
• Groups C, D and F (combinations): limiting immune-related toxicity during prior checkpoint inhibitor therapy.
• Group F only: Previous treatment with LAG-# or TIM-3 therapy or lenvatinib; multiple metastases that achieved mixed tumor response to prior anti-PD-(L)1 therapy
• Has an active autoimmune disease requiring systemic immunosuppression with corticosteroids (\> 10 mg/day of prednisone or equivalent) or immunosuppressive drugs within 14 days before the first dose of study treatment.
• Receiving chronic systemic steroids (\> 10 mg/day of prednisone or equivalent):
• Has received a live vaccine within 28 days of the planned start of study treatment.

Other illness

• Has disease eligible for potentially curative treatment.
• Has known active hepatitis B or C.
• Evidence of interstitial lung disease or active, noninfectious pneumonitis.
• Participants who are known to be HIV-positive with some protocol exceptions.

Other

• Group A, B and E only: Histologically confirmed diagnosis of carcinosarcoma of the uterus.
• Histologically confirmed diagnosis of sarcoma of the uterus.
• Known active CNS metastases and/or carcinomatous meningitis.

• Ability to comprehend and willingness to sign a written ICF for the study. Note for Germany: This excludes individuals who are housed in an institution due to official or court order Women 18 years of age or older (or as applicable per local country requirements).
• Histologically confirmed diagnosis of advanced or metastatic endometrial cancer with disease progression on or after treatment with at least 1 platinum-containing regimen for advanced or metastatic disease.
• Groups A, B, and E: Have not been previously treated with a PD-(L)1 inhibitor.
• Group A only: Tumor tissue tested as MSI-High
• Group B only: Tumor tissue tested as deficient MMR or an ultra-mutated POLE tumor.
• Group D only: Tumor tissue tested as having an FGFR 1,2,3 mutation or alteration characterized as per protocol.
• Group E: Tumor tissue tested as MSS and PD-L1 positive.
• Group F: Radiological evidence of disease progression on or after prior PD (L)1 therapy and Tumor tissue tested as MSI-H
• Must have at least 1 measurable tumor lesion per RECIST v1.1.
• Willing to provide tumor tissue sample (fresh or archived).
• ECOG performance status 0 to 1.
• Willingness to avoid pregnancy.