Key Inclusion Criteria:

          1. Patients with histologically or cytologically documented squamous or non-squamous
             NSCLC who either have stage IIIb or stage IIIc disease who are not candidates for
             treatment with definitive concurrent chemo-radiation or have stage IV disease.
             Patients must have PD after receiving one prior line of chemotherapy treatment for
             advanced NSCLC.

          2. Availability of an archival or on-study obtained formalin-fixed, paraffin-embedded
             tumor tissue biopsy sample

          3. Biopsy evaluable for expression of PD-L1 as determined by a PD-L1 Immunohistochemistry
             (IHC) pharma diagnostic test (pharmDx) assay performed by a central laboratory

          4. At least 1 radiographically measureable lesion by computed tomography (CT) per RECIST
             1.1 criteria

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

        Key Exclusion Criteria:

          1. Patients who have never smoked, defined as smoking ≤100 cigarettes in a lifetime

          2. Active or untreated brain metastases or spinal cord compression

          3. Patients with tumors tested positive for epidermal growth factor receptor (EGFR) gene
             mutations, anaplastic lymphoma kinase (ALK) gene translocations, or C-ros oncogene
             receptor tyrosine kinase (ROS1) fusions

          4. Encephalitis, meningitis, or uncontrolled seizures in the year prior to randomization

          5. History of interstitial lung disease (eg, idiopathic pulmonary fibrosis or organizing
             pneumonia), or active, noninfectious pneumonitis that required immune-suppressive
             doses of glucocorticoids to assist with management, or of pneumonitis within the last
             5 years

          6. Ongoing or recent evidence of significant autoimmune disease that required treatment
             with systemic immunosuppressive treatments, which may suggest a risk of immunerelated
             treatment-emergent adverse events (irTEAEs)

          7. Patients with a condition requiring corticosteroid therapy (>10 mg prednisone/day or
             equivalent) within 14 days of randomization

        Note: Other protocol defined Inclusion/Exclusion criteria apply.