At the Thirteenth International Kidney Cancer Symposium, Dr Hans Hammers (Johns Hopkins, MD) discusses the Phase 1 clinical trial that studied the immune checkpoint inhibitors, nivolumab and ipilimumab, in metastatic renal cell carcinoma (mRCC). The primary endpoint was to access safety and tolerability, and the secondary endpoint was to access efficacy. Overall, side effects were manageable and objective response was greater than previously reported with nivolumab monotherapy. These findings directed a subsequent Phase 3 trial.