Inclusion Criteria:

• Patients 18 years of age or older
• Definitive diagnosis of unresectable advanced or metastatic RCC with clear-cell histology and/or sarcomatoid carcinoma
• Evaluable Memorial Sloan Kettering Cancer Center (MSKCC) risk score
• Measurable disease as defined by Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1)
• Karnofsky performance status (KPS) greater than or equal to 70
• Adequate hematologic and end-organ function

Exclusion Criteria:

• Radiotherapy for RCC within 14 days prior to treatment
• Active or untreated central nervous system (CNS) metastases
• Uncontrolled pleural effusion, pericardial effusion, or ascites
• Uncontrolled hypercalcemia
• Any other malignancies within 5 years except those with negligible risk of metastasis or death
• Life expectancy less than 12 weeks
• Participation in another experimental drug study within 4 weeks prior to treatment
• Pregnant or lactating women
• Known hypersensitivity to any component of Atezolizumab or other study medication
• History of autoimmune disease except controlled, treated hypothyroidism or type I diabetes
• History of idiopathic pulmonary fibrosis, organizing pneumonia, drug-induced pneumonitis, or idiopathic pneumonitis
• Positive human immunodeficiency virus (HIV) test
• Active hepatitis B or C
• Severe infection within 4 weeks prior to treatment
• Exposure to oral or intravenous (IV) antibiotics within 2 weeks or live attenuated vaccines within 4 weeks prior to treatment
• Significant cardiovascular disease
• Prior allogeneic bone marrow or solid organ transplantation
• Prior treatment with CD137 agonists, anti-CTLA4, anti-PD-1, or anti-PD-L1 therapeutic antibody or pathway-targeting agents
• Treatment with immunostimulatory agents within 6 weeks or immunosuppressive agents within 2 weeks prior to treatment
• History of hypertensive crisis or hypertensive encephalopathy