A Study of Atezolizumab in Participants With Programmed Death-Ligand 1 (PD-L1) Positive Locally Advanced or Metastatic Non-Small Cell Lung Cancer (NSCLC) [FIR]

This multicenter, single-arm study will evaluate the efficacy and safety of atezolizumab (MPDL3280A) in participants with PD-L1-positive locally advanced or metastatic NSCLC. Participants will receive an intravenous (IV) dose of 1200 milligrams (mg) atezolizumab (MPDL3280A) on Day 1 of 21-day cycles until disease progression. Eligible participants will be categorized in to three groups as follows: 1. Participants with no prior chemotherapy for advanced disease; 2. Participants who progress during or following a prior-platinum based chemotherapy regimen for advanced disease (2L+participants); 3. Participants who are 2L+ and previously treated for brain metastases.