Pembrolizumab (MK-3475) Plus Epacadostat vs Standard of Care in mRCC (KEYNOTE-679/ECHO-302)

Inclusion Criteria: * Histologic confirmation of locally advanced or metastatic RCC with a clear-cell component with or without sarcomatoid features. * Must not have received any prior systemic therapy for their mRCC. * Measurable disease based on RECIST v1.1. * Archival tumor tissue sample or newly obtained core or excisional biopsy of a tumor lesion as required. * Karnofsky performance status ≥ 70%. * Adequate organ function per protocol-defined criteria. Exclusion Criteria: * Use of protocol-defined prior/concomitant therapy. * Currently receiving or has received an investigational treatment as part of a study of an investigational agent or has used an investigational device within 4 weeks before randomization. * History of severe hypersensitivity reaction to study treatments or their excipients. * Active autoimmune disease that has required systemic treatment in past 2 years. * Known additional malignancy that has progressed or has required active treatment in the last 3 years. * Known active central nervous system metastases and/or carcinomatous meningitis. * History of (noninfectious) pneumonitis that required steroids or current pneumonitis. * History or presence of an abnormal electrocardiogram that, in the investigator's opinion, is clinically meaningful. * Significant cardiac event within 12 months before Cycle 1 Day 1.