Nivolumab Alone or in Combination With Ipilimumab in Treating Patients With Advanced Uterine Leiomyosarcoma

Inclusion Criteria: * Patients must have histologically or cytologically confirmed advanced leiomyosarcoma of the uterus (ULMS); advanced ULMS is defined as metastatic ULMS or unresectable primary ULMS * Patients must have measurable disease, defined as at least one lesion that can be accurately measured in at least one dimension (longest diameter to be recorded for non-nodal lesions and short axis for nodal lesions) as \>= 20 mm (\>= 2 cm) with conventional techniques or as \>= 10 mm (\>= 1 cm) with spiral computed tomography (CT) scan, magnetic resonance imaging (MRI), or calipers by clinical exam * Patients must have received at least one prior line of chemotherapy, for ULMS (either in the adjuvant or metastatic setting) * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 * Life expectancy of greater than 9 months * Absolute neutrophil count \>= 1,500/mcL * Platelets \>= 100,000/mcL * Total bilirubin =\< 1.5 x institutional upper limit of normal (ULN) (except patients with Gilbert syndrome, who can have total bilirubin \< 3.0 mg/dL) * Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase \[SGOT\])/alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase \[SGPT\]) =\< 2.5 x ULN/ =\< 5 x ULN for subjects with liver metastases * Serum creatinine =\< 1.5 x ULN OR creatinine clearance (CrCl) \>= 50 mL/min (if using the Cockcroft-Gault formula) * Patients with a requirement for steroid treatment or other immunosuppressive tr…