A Study of Tiragolumab in Combination With Atezolizumab Plus Pemetrexed and Carboplatin/Cisplatin Versus Pembrolizumab Plus Pemetrexed and Carboplatin/Cisplatin in Participants With Previously Untreated Advanced Non-Squamous Non-Small Cell Lung Cancer

Key Inclusion Criteria:

Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1
Histologically or cytologically documented locally advanced unresectable or metastatic non-squamous NSCLC that is not eligible for curative surgery and/or definitive chemoradiotherapy
No prior systemic treatment for metastatic non-squamous NSCLC
Known tumor programmed death-ligand 1 (PD-L1) status
Measurable disease, as defined by Response Evaluation Criteria in Solid Tumors, version 1.1 (RECIST v1.1)
Life expectancy >= 12 weeks
Adequate hematologic and end-organ function
Negative human immunodeficiency virus (HIV) test at screening
Serology test negative for active hepatitis B virus or active hepatitis C virus at screening.

Key Exclusion Criteria:

Mutations in epidermal growth factor receptor (EGFR) gene or anaplastic lymphoma kinase (ALK) fusion oncogene
Pulmonary lymphoepithelioma-like carcinoma subtype of NSCLC
Symptomatic, untreated, or actively progressing central nervous system (CNS) metastases
Active or history of autoimmune disease or immune deficiency
History of idiopathic pulmonary fibrosis, organizing pneumonia, drug-induced pneumonitis, or idiopathic pneumonitis, or evidence of active pneumonitis
History of malignancy other than NSCLC within 5 years prior to randomization, with the exception of malignancies with a negligible risk of metastasis or death
Severe infection within 4 weeks prior to initiation of study treatment or any active infection that, in the opinion of the investigator, could impact patient safety
Treatment with investigational therapy within 28 days prior to initiation of study treatment
Prior treatment with CD137 agonists or immune checkpoint blockade therapies, including anti-cytotoxic T lymphocyte-associated protein 4, anti-TIGIT, anti-PD-1, and anti-PD-L1 therapeutic antibodies
Treatment with systemic immunostimulatory agents within 4 weeks or 5 drug-elimination half-lives (whichever is longer) prior to initiation of study treatment
Treatment with systemic immunosuppressive medication within 2 weeks prior to initiation of study treatment, or anticipation of need for systemic immunosuppressive medication during study treatment
Known allergy or hypersensitivity or other contraindication to any component of the chemotherapy regimen the participant may receive during the study
Women who are pregnant, or breastfeeding
Known targetable c-ROS oncogene 1 (ROS1) or BRAFV600E genomic aberration.