A Study of Atezolizumab in High PD-L1 Expression, Chemotherapy-Naïve Patients With Stage IV Non-Squamous or Squamous Non-Small Cell Lung Cancer

Inclusion Criteria: * ECOG performance status of 0 or 1. * Histologically or cytologically confirmed, Stage IV non-squamous or squamous NSCLC. * No prior treatment for Stage IV non-squamous or squamous NSCLC. * Patients who have received prior neo-adjuvant, adjuvant chemotherapy, radiotherapy, or chemo-radiotherapy with curative intent for non-metastatic disease must have experienced a treatment free interval of at least 6 months from enrollment since the last chemotherapy, radiotherapy, or chemo-radiotherapy cycle. * Tumor TC3 or IC3, as determined by SP142 performed by a central laboratory on previously obtained archival tumor tissue or tissue obtained from a biopsy at screening. * Measurable disease, as defined by RECIST v1.1. * Adequate hematologic and end-organ function. * Life expectancy ≥3 months. * For women of childbearing potential: agreement to remain abstinent or use contraception, and agreement to refrain from donating. Exclusion Criteria: * Known sensitizing mutation in the EGFR gene or ALK fusion oncogene. * Symptomatic, untreated, or actively progressing CNS metastases. * Spinal cord compression not definitively treated with surgery and/or radiation, or previously diagnosed and treated spinal cord compression without evidence that disease has been clinically stable for ≥2 weeks prior to enrollment. * Current leptomeningeal disease. * Uncontrolled tumor-related pain. * Uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent drainage procedures. * Uncontrolled or symptomatic hypercalcemia. * Malignancies other than NSCLC within 5 years prior to enrollment, with the exception of those with a negligible risk of metastasis or death treated with expected curative outcome. * Pregnancy or breastfeeding, or intention of becoming pregnant during study treatment or within at least 5 months after the last dose of atezolizumab. * History of severe allergic, anaphylactic, or other hypersensitivity reactions to chimeric or humanized antibodies or fusion proteins. * Known allergy or hypersensitivity to biopharmaceuticals produced in Chinese hamster ovary cells or any component of the atezolizumab formulation. * Active or history of autoimmune disease or immune deficiency. * History of idiopathic pulmonary fibrosis, organizing pneumonia, drug-induced pneumonitis, idiopathic pneumonitis, or evidence of active pneumonitis on screening chest CT scan. * Positive human immunodeficiency virus (HIV) test result at screening. * Patients with active hepatitis B or active hepatitis C at screening. * Active tuberculosis. * Severe infections within 4 weeks prior to randomization, including, but not limited to, hospitalization for complications of infection, bacteremia, or severe pneumonia. * Significant cardiovascular disease.