This phase 3 trial compared the efficacy and safety of nivolumab plus ipilimumab versus sunitinib in previously untreated advanced renal-cell carcinoma. The primary end points were overall survival, objective response rate, and progression-free survival among intermediate- and poor-risk patients. A total of 1096 patients were randomized 1:1 to receive either nivolumab plus ipilimumab or sunitinib. The 18-month overall survival rate was 75% with nivolumab plus ipilimumab versus 60% with sunitinib (hazard ratio, 0.63; P<0.001). The objective response rate was 42% with nivolumab plus ipilimumab versus 27% with sunitinib (P<0.001). The median overall survival was not reached with nivolumab plus ipilimumab versus 26.0 months with sunitinib. Treatment-related adverse events were common but generally manageable, with a lower incidence of grade 3 and 4 events with nivolumab plus ipilimumab. The safety profile was consistent with previous studies. This trial demonstrated that nivolumab plus ipilimumab is superior to sunitinib in terms of overall survival and objective response rate in intermediate- and poor-risk patients with advanced renal-cell carcinoma.This phase 3 trial compared the efficacy and safety of nivolumab plus ipilimumab versus sunitinib in previously untreated advanced renal-cell carcinoma. The primary end points were overall survival, objective response rate, and progression-free survival among intermediate- and poor-risk patients. A total of 1096 patients were randomized 1:1 to receive either nivolumab plus ipilimumab or sunitinib. The 18-month overall survival rate was 75% with nivolumab plus ipilimumab versus 60% with sunitinib (hazard ratio, 0.63; P<0.001). The objective response rate was 42% with nivolumab plus ipilimumab versus 27% with sunitinib (P<0.001). The median overall survival was not reached with nivolumab plus ipilimumab versus 26.0 months with sunitinib. Treatment-related adverse events were common but generally manageable, with a lower incidence of grade 3 and 4 events with nivolumab plus ipilimumab. The safety profile was consistent with previous studies. This trial demonstrated that nivolumab plus ipilimumab is superior to sunitinib in terms of overall survival and objective response rate in intermediate- and poor-risk patients with advanced renal-cell carcinoma.