A Study of Atezolizumab in Combination With Carboplatin + Paclitaxel or Carboplatin + Nab-Paclitaxel Compared With Carboplatin + Nab-Paclitaxel in Participants With Stage IV Squamous Non-Small Cell Lung Cancer (NSCLC) [IMpower131]

Inclusion Criteria:

Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1
Histologically or cytologically confirmed, treatment-naïve Stage IV squamous NSCLC
Previously obtained archival tumor tissue or tissue obtained from biopsy at screening
Measurable disease as defined by RECIST v1.1
Adequate hematologic and end organ function

Exclusion Criteria:

Active or untreated central nervous system (CNS) metastasis
Malignancies other than NSCLC within 5 years prior to randomization, with the exception of those with a negligible risk of metastasis or death treated with expected curative outcome
Pregnant or lactating women
History of autoimmune disease
History of idiopathic pulmonary fibrosis, organizing pneumonia, drug-induced pneumonitis, idiopathic pneumonitis, or evidence of active pneumonitis on screening chest Computed Tomography (CT) scan, History of radiation pneumonitis in the radiation field (fibrosis) is permitted
Positive test for Human Immunodeficiency Virus (HIV)
Active hepatitis B or hepatitis C
Prior treatment with cluster of differentiation 137 (CD137) agonists or immune checkpoint blockade therapies, anti-programmed death-1 (anti-PD-1), and anti-PD-L1 therapeutic antibody
Severe infection within 4 weeks prior to randomization
Significant history of cardiovascular disease