Nivolumab With and Without Ipilimumab and Radiation Therapy in Treating Patients With Recurrent or Resectable Undifferentiated Pleomorphic Sarcoma or Dedifferentiated Liposarcoma Before Surgery

This phase II trial studies how well nivolumab with and without ipilimumab and radiation therapy when given before surgery works in treating patients with undifferentiated pleomorphic sarcoma or dedifferentiated liposarcoma that can be removed by surgery. Immunotherapy with monoclonal antibodies, such as nivolumab and ipilimumab, may help the body\'s immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Radiation therapy uses high energy x-rays to kill tumor cells and shrink tumors. Giving nivolumab, ipilimumab, and radiation therapy may work better in treating patients with undifferentiated pleomorphic sarcoma.