Background: Trials of neoadjuvant and adjuvant chemotherapy have demonstrated an absolute survival benefit of 5% for patients with early stage disease. Atezolizumab is a humanized IgG1 monoclonal antibody that inhibits PD-L1 from binding to its receptors PD-1 and B7.1, thereby restoring anti-tumor immune response. In the OAK trial, a randomized phase III trial of patients with metastatic NSCLC who progressed on platinum based chemotherapy, atezolizumab improved overall survival in patients regardless of PD-L1 expression compared with docetaxel (13.8 months vs. 9.6 months, HR 0.73 [95% CI 0.62 – 0.87]) with a manageable safety profile. Methods: NCT02927301 is a phase II, open-label, single-arm study designed to evaluate the efficacy and safety of atezolizumab as a neoadjuvant and adjuvant therapy in patients with Stage IB, II, or IIIA NSCLC prior to curative-intent resection. Approximately 180 patients with NSCLC will be enrolled in this study at 15 academic medical centers in the United States. The study has two parts: the primary part will evaluate the ability of neoadjuvant atezolizumab to produce pathologic responses in patients with early stage NSCLC. Atezolizumab 1200 mg IV will be given every 3 weeks for two doses. Surgical resection of tumors following treatment will allow determination of pathologic response rates and potential predictive biomarkers. Part 2 is exploratory and will evaluate atezolizumab adjuvant therapy for up to 12 months in patients who demonstrate clinical benefit in Part 1. The primary endpoint is major pathologic response rate (defined as ≤ 10% of viable tumor tissue) based on surgical resection. Secondary end points include overall response rate by status of mutation load, neoantigen score and gene expression signatures. OS and DFS are exploratory end points. This trial presents a unique opportunity to evaluate exploratory biomarkers given the availability of pre- and post-treatment biopsy specimens for assessment of evolution of immune related markers associated with response. The study opened to accrual in January 2017. Clinical trial information: NCT02927301