CTLA4 and renal cell carcinoma: The purpose of the open-label, randomized phase 2 FRACTION-RCC platform trial (NCT02996110) is to test the efficacy and safety of various combinations of nivolumab compared with nivolumab and ipilimumab in participants with advanced RCC that has progressed on or after ICI (participants undergoing anti-CTLA-4 therapy were eligible).