Nivolumab Combined With Ipilimumab for Patients With Advanced Rare Genitourinary Tumors

This research study is a Phase II clinical trial. Phase II clinical trials test the safety and effectiveness of an investigational drug to learn whether the combination of drugs works in treating a specific disease. "Investigational" means that the drugs are being studied. The FDA (the U.S. Food and Drug Administration) has not approved nivolumab in combination with ipilimumab for this specific disease but the combination is approved for use in melanoma patients. In this research study, the investigators are... * Investigating the response of the participant's cancer to treatment with nivolumab plus ipilimumab, * Assessing the safety of treatment with nivolumab and ipilimumab and * Evaluating response and resistance to treatment by looking at the participant's tumor tissue and blood for markers to predict response and resistance to therapy.