A Study of Atezolizumab (an Engineered Anti-Programmed Death-Ligand 1 [PD-L1] Antibody) as Monotherapy or in Combination With Bevacizumab (Avastin®) Compared to Sunitinib (Sutent®) in Participants With Untreated Advanced Renal Cell Carcinoma

Inclusion Criteria:

Unresectable advanced or metastatic renal cell carcinoma with component of clear cell histology and/or component of sarcomatoid histology that has not been previously treated with any systemic agents, including treatment in the adjuvant setting
Measurable disease, as defined by RECIST v1.1
Karnofsky performance score greater than or equal to (>/=) 70
Adequate hematologic and end-organ function as defined by protocol
Women of childbearing potential and male participants with partners of childbearing potential must agree to use highly effective methods of contraception as defined by protocol

Exclusion Criteria:

Disease-Specific Exclusions:

Radiotherapy for renal cell carcinoma within 14 days prior to Cycle 1, Day 1 with the exception of single-fraction radiotherapy given for the indication of pain control
Known active malignancies or metastasis of the brain or spinal cord or leptomeningeal disease, as determined by computed tomography (CT) or magnetic resonance imaging (MRI) evaluation during screening and prior radiographic assessments
Uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent drainage procedures (once monthly or more frequently)
Uncontrolled hypercalcemia or symptomatic hypercalcemia
Malignancies other than renal cell carcinoma within 5 years prior to Cycle 1, Day 1, with the exception of those with a negligible risk of metastasis or death, treated with expected curative outcome

General Medical Exclusions:

Life expectancy of less than (<) 12 weeks
Pregnant and lactating women
History of severe allergic, anaphylactic, or other hypersensitivity reactions to chimeric or humanized antibodies or fusion proteins
History of autoimmune disease
History of idiopathic pulmonary fibrosis, organizing pneumonia, drug-induced pneumonitis, idiopathic pneumonitis, or evidence of active pneumonitis on screening chest CT scan
Participants with active or chronic hepatitis B, active hepatitis C, Human Immunodeficiency Virus (HIV) positive test, significant cardiovascular disease
Prior allogeneic stem cell or solid organ transplant

Exclusion Criteria Related to Medications:

Prior treatment with Cluster of Differentiation 137 (CD137) agonists, anti-Cytotoxic T-Lymphocyte Antigen-4 (anti-CTLA-4), anti-programmed death-1 (anti-PD-1), or anti-PD-L1 therapeutic antibody or pathway-targeting agents
Treatment with systemic immunostimulatory agents for any reason within 6 weeks or five half-lives of the drug, whichever is shorter, prior to Cycle 1, Day 1
Treatment with systemic immunosuppressive medications within 2 weeks prior to Cycle 1, Day 1

Bevacizumab- and Sunitinib-Specific Exclusions:

Inadequately controlled hypertension
Prior history of hypertensive crisis or hypertensive encephalopathy
New York Heart Association Class II or greater congestive heart failure
History of myocardial infarction or unstable angina, stroke or transient ischemic attack within 3 months prior to Cycle 1, Day 1