Immunotherapy + Radiation in Resectable Soft Tissue Sarcoma

Inclusion Criteria: * Diagnosed with biopsy-proven soft-tissue sarcoma with confirmatory pathology review at University of Rochester Medical Center (URMC) * 18 years or older. * Able to provide informed consent. * Resectable disease per surgical evaluation. * Neoadjuvant/preoperative radiotherapy has been recommended * Intermediate to high grade sarcoma on biopsy, tumor \> 5 cm in size by imaging * Willing to have blood draws for flow cytometry and Serametrix analysis. * Willing to receive neoadjuvant radiation therapy and subsequent surgical resection. * Patients with known human immunodeficiency virus (HIV) are eligible if the lymphocytes \> 350 CD4+ cells and no detectable viral load. * Women of childbearing potential (defined as any woman, who 1) has not undergone tubal ligation, a hysterectomy or bilateral oophorectomy; or 2) has not been naturally postmenopausal for at least 24 consecutive months or has had menses at any time in the preceding 24 consecutive months): * Must not be pregnant or nursing * Must have a negative pregnancy test done within 7 days prior to registration as well as within 72 hrs. prior to receiving first dose of study medication * Women of childbearing potential must use at least two other accepted and highly-effective methods of contraception and/or agree to abstain from sexual intercourse for at least 5 months after the last dose of nivolumab and/or ipilimumab. * Should a woman become pregnant or suspect she is pregnant while she is pa…