This study is for patients that have recurrent/persistent endometrial cancer. The investigational drug used in this study is Sacituzumab Govitecan (SG). Investigational means it has not been approved by the United States Food and Drug Administration (FDA). The study drug is given to participants through infusion. The primary purpose of the study is to compare the effect of SG relative to treatment of physician's choice (TPC) on progression-free survival (PFS) and on overall survival (OS). Participants can expect to be on this study until their demise.