A Study Evaluating the Efficacy and Safety of Multiple Therapies in Cohorts of Participants With Locally Advanced, Unresectable, Stage III Non-Small Cell Lung Cancer (NSCLC)

Inclusion Criteria (All Cohorts): * Body weight ≥ 30 kilograms (kg) at screening * Willingness and ability to use the electronic device(s) or application(s) for the electronic patient-reported outcome (PRO) * Whole-body positron emission tomography/computed tomography scan (PET/CT) (from the base of skull to mid-thighs) for the purposes of staging, performed prior and within 42 days for Cohort A2 (ROS1 positive) and 50 days for Cohort A1 (ALK positive) of the first dose of concurrent chemoradiotherapy (cCRT) or sequential chemoradiotherapy (sCRT) * Histologically or cytologically documented locally advanced, unresectable Stage III NSCLC of either squamous or non-squamous histology * Prior receipt of at least two prior cycles of platinum-based chemotherapy given cCRT; or at least two prior cycles of platinum-based chemotherapy given prior to radiotherapy (sCRT) * The RT component in the cCRT or sCRT must have been at a total dose of radiation of 60 (+/-10%) Gy (54 Gy to 66 Gy) administered by intensity-modulated radiotherapy (preferred) or three dimension (3D)-conforming technique * No disease progression during or following platinum-based cCRT or sCRT * Life expectancy ≥ 12 weeks * Confirmed availability of a representative formalin-fixed, paraffin-embedded (FFPE) tumor specimen * Tumor programmed death-ligand 1 (PD-L1) status (TC score \< 1% vs. ≥ 1% vs. unknown) as determined using the VENTANA PD-L1 IHC SP263 assay (preferred) or the Dako PD-L1 IHC 22C3 pharmDx assay * Eas…