Background: The anti–PD-L1 mAb atezo blocks the interaction between PD-L1 and its receptors PD-1 and B7.1 and restores anti-tumor immunity. In the OAK trial, pts with 2L/3L advanced NSCLC had improved mOS in the atezo arm (13.8 mo) vs the docetaxel (doc) arm (9.6 mo), with a survival benefit observed regardless of PD-L1 expression levels on tumor cells (TC) or tumor-infiltrating immune cells (IC). However, more effective treatment options are needed for pts with early-stage NSCLC. A global Phase III, randomized, open-label trial, IMpower010 (NCT02486718), is being conducted to evaluate the efficacy and safety of atezo vs BSC following adjuvant cisplatin (cis)–based chemotherapy (chemo) in pts with resected stage IB (tumors ≥ 4 cm)-IIIA NSCLC. Methods: Pts eligible for study must have complete tumor resection 4 to 12 weeks prior to enrollment for pathologic stage IB (tumors ≥ 4 cm)-IIIA NSCLC, be adequately recovered from surgery, be able to receive cis-based adjuvant chemo and have an ECOG PS 0-1. Pts with other malignancies, autoimmune disease, hormonal cancer or radiation therapy within 5 years and prior chemo or immunotherapy are excluded from study. Approximately 1127 pts will be enrolled regardless of PD-L1 status. Pts will receive up to four 21-d cycles of cis-based chemo (cis [75 mg/m² IV, d 1] + vinorelbine [30 mg/m² IV, d 1, 8], doc [75 mg/m² IV, d 1] or gemcitabine [1250 mg/m² IV, d 1, 8], or pemetrexed [500 mg/m² IV, d 1; only non-squamous NSCLC]). No adjuvant radiation therapy is permitted. After adjuvant chemo, eligible pts will be randomized 1:1 to receive 16 cycles of atezo 1200 mg q3w or BSC. Stratification factors include sex, histology (squamous vs non-squamous), disease stage (IB vs II vs IIA) and PD-L1 status by IHC (TC2/3 [≥ 5% expressing PD-L1] and any IC vs TC0/1 [ < 5%] and IC2/3 vs TC0/1 and IC0/1 [ < 5%]). The primary endpoint is disease-free survival; secondary endpoints include OS and safety. Exploratory biomarkers, including PD-L1 expression, immune- and tumor-related biomarkers before, during and after treatment with atezo and at radiographic disease recurrence, or confirmation of new primary NSCLC, will be evaluated. Clinical trial information: NCT02486718