Additional Study Information: This study is for patients who have renal cell carcinoma (RCC; a type of kidney cancer) and are at a high risk of disease coming back (disease recurrence) following either nephrectomy (surgical procedure to remove all or part of a kidney) or metastasectomy (removal of cancerous growth that has spread away from your kidney). The purpose of this study is to compare the effects, good or bad, of atezolizumab versus placebo (an inactive substance that looks like atezolizumab) on RCC to find out which is better.