• Patients with non-squamous or squamous histology NSCLC with stage IIIB or stage IIIC disease who are not candidates for surgical resection or definitive chemoradiation per investigator assessment or stage IV (metastatic disease), who received no prior systemic treatment for recurrent or metastatic NSCLC.

• Availability of an archival or on-study formalin-fixed, paraffin-embedded (FFPE) tumor tissue sample, without intervening therapy between biopsy collection and screening as described in the protocol

• For enrollment in phase 2, patients should have PD-L1 levels ≥ 50%, as determined by a College of American Pathologists (CAP)/Clinical Laboratory Improvement Amendments (CLIA) (or equivalently licensed, according to local regulations) accredited laboratory, as described in the protocol. For enrollment in phase 3, patients should have expression of programmed cell death ligand-1 (PD-L1) in ≥50% of tumor cells stained using an assay performed by a central laboratory, as described in the protocol.

• At least 1 radiographically measurable lesion by computed tomography (CT) or magnetic resonance imaging (MRI) per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1) criteria. Target lesions may be located in a previously irradiated field if there is documented (radiographic) disease progression in that site.

• Eastern Cooperative Oncology Group (ECOG) performance status of ≤1.

• Adequate organ and bone marrow function, as described in the protocol.