The vast majority of patients with stage I (tumors ≥ 4cm), IIA, IIB (and select stage III) NSCLC are managed with upfront surgery, followed by adjuvant chemotherapy. However, relapse rates remain high and are primarily due to distant, metastatic disease. Previous meta-analysis evaluating the use of neo-adjuvant chemotherapy and adjuvant chemotherapy demonstrate a similar impact on improved disease free survival (DFS) and overall survival (OS). The role of checkpoint inhibitors has been proven to be effective in the treatment of patients with advanced NSCLC, regardless of histology and PD-L1 expression. Results from trials evaluating the use of checkpoint inhibitors alone or in combination with chemotherapy in the neoadjuvant setting for early stage disease are promising. However, there are no trials evaluating the role of concomitant chemotherapy and checkpoint inhibitors in the adjuvant setting. In addition, emerging data supports the use of ctDNA as a promising biomarker for early detection of minimal residual disease and have indicated that the presence of detectable ctDNA after surgery for localized lung cancer is correlated with a 90-100% chance for disease recurrence. Therefore, we propose this current study assessing concomitant chemotherapy plus Atezolizumab in the adjuvant setting for patients with stage I (tumors ≥ 4cm), IIA, IIB (and select stage III) NSCLC who have detectable ctDNA after surgery. The clearance of ctDNA will serve as a surrogate for long term DFS and OS in this patient population.