There is no curative treatment for patients with NSCLC who develop metastatic disease after resection. Trials of neoadjuvant and adjuvant chemotherapy have demonstrated an absolute survival benefit of 5% for patients with stages IB, II, and IIIA disease. Clearly, developing new treatment strategies to improve survival following resection is critical to improving outcomes for this patient population. Immunotherapy with checkpoint inhibitors such as antibodies to PD-1 and PD-L1 has demonstrated superior survival compared to chemotherapy in randomized clinical trials. PD-L1 expression is being investigated as a predictive biomarker for these therapies, but its ability to predict response has varied in published trials. Atezolizumab is a humanized IgG1 monoclonal PD-L1 antibody that was recently evaluated in the POPLAR trial (NCT01903993), a phase II randomized trial of patients with NSCLC who progressed on platinum based chemotherapy. Atezolizumab therapy improved overall survival compared with docetaxel (12.6 months vs. 9.7 months, HR 0.73 [95% CI 0.53 – 0.99]) with a manageable safety profile. Improvement in survival correlated with PD-L1 immunohistochemistry expression of tumor and tumor-infiltrating immune cells. Trial design: This phase II, open-label, single-arm study is designed to evaluate the efficacy and safety of atezolizumab as a neoadjuvant 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. There are two parts to this study: the first/primary part will evaluate the ability of neoadjuvant atezolizumab to produce objective 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 (evidence of pathologic response or absence of radiographic progression) in Part 1. After surgical resection, patients may receive SOC adjuvant chemotherapy (with or without radiation) before starting atezolizumab adjuvant therapy in Part 2. The primary objectives are safety and major pathologic response based on surgical resection. Secondary objectives include overall response rate based on PD-L1 status, mutational load, antigen burden, and RNA-sequencing. This trial presents a unique opportunity to evaluate exploratory biomarkers, including pre- and post-treatment biopsy assessment of evolution of immune related markers associated with response. Section not applicable. Section not applicable.