Study to Evaluate the Efficacy and Safety of Pembrolizumab (MK-3475) in Combination With Axitinib Versus Sunitinib Monotherapy in Participants With Renal Cell Carcinoma (MK-3475-426/KEYNOTE-426)

The purpose of this study is to evaluate the efficacy and safety of pembrolizumab (MK-3475) in combination with axitinib versus sunitinib monotherapy as a first-line treatment for participants with advanced/metastatic renal cell carcinoma (mRCC). The primary hypotheses of this study are: 1. The combination therapy of pembrolizumab plus axitinib is superior to sunitinib monotherapy with respect to Progression-Free Survival (PFS) as assessed by blinded independent central imaging review per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1) 2. The combination therapy of pembrolizumab plus axitinib is superior to sunitinib monotherapy with respect to Overall Survival (OS).