This is a single arm open label Phase I/II study that will consist of two parts. In Phase I, investigators will assess the safety and tolerability of SBRT combined with Avelumab. In Phase II, investigators will determine whether SBRT combined with Avelumab improves relapse free survival. Subjects with Stage I NSCLC who are not undergoing surgical resection will be candidates for enrollment. Subjects will receive definitive stereotactic body radiation (SBRT) in 4-5 fractions combined with concurrent and adjuvant Avelumab at 10mg/kg for a total of 6 cycles. Subjects will be evaluated for safety as measured by the occurrence of adverse events, serious adverse events, and laboratory abnormalities. Three blood draws will be obtained to analyze anti-tumor immune responses and immune correlates.
