A Study of Atezolizumab Compared With Gemcitabine Plus (+) Cisplatin or Carboplatin for PD-L1-Selected Participants With Stage IV Squamous Non-Small Cell Lung Cancer (NSCLC) (IMpower111)

Inclusion Criteria:

• Histologically or cytologically confirmed Stage IV squamous NSCLC

• Tumor programmed death-ligand 1 (PD-L1) expression, as determined byimmunohistochemistry (IHC) assay of archival tumor tissue or tissue obtained atscreening

• No prior treatment for Stage IV squamous NSCLC

• Measurable disease as defined by RECIST v1.1

• Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1

• Adequate hematologic and end-organ function

Exclusion Criteria:

• Active or untreated central nervous system (CNS) metastases

• Untreated or inadequately treated spinal cord compression

• Leptomeningeal disease

• Uncontrolled pleural effusion, pericardial effusion, or ascites

• Uncontrolled tumor-related pain

• Uncontrolled hypercalcemia

• Any other malignancies within 5 years except those with negligible risk of metastasisor death

• Pregnant or lactating women

• Known hypersensitivity to any component of atezolizumab formulation or other studymedication

• History of autoimmune disease except controlled, treated hypothyroidism or type Idiabetes

• Prior allogeneic bone marrow or solid organ transplantation

• Positive human immunodeficiency virus (HIV) test

• Active hepatitis B or C

• Active tuberculosis

• Significant cardiovascular disease

• Severe infection or major surgery within 4 weeks prior to randomization

• Use of any approved anti-cancer therapy within 3 weeks prior to treatment

• Use of an investigational agent or participation in another clinical trial within 4weeks prior to randomization

• Exposure to oral or IV antibiotics within 2 weeks or live attenuated vaccines within 4weeks prior to randomization

• Prior treatment with cluster of differentiation (CD) 137 agonists or immune checkpointblockade therapies, anti-programmed death-1 (anti-PD-1), and anti-PD-L1 therapeuticantibodies

• Treatment with immunostimulatory agents within 4 weeks or immunosuppressive agentswithin 2 weeks prior to randomization