Inclusion Criteria:

• Age ≥ 18 years
• Have an Eastern Cooperative Oncology Group (ECOG) performance status of ≤ 2
• Diagnosed with T1-3N0 biopsy-proven NSCLC of the lung. Multiple primary lung tumors are allowed; however, each lesion requires histologic confirmation
• Metachronous lung tumors as defined as a new lung lesion in the setting of a historically treated lung cancer are allowed under certain conditions. The previous lung cancer must have been treated greater than 6 months prior to protocol therapy and this cancer must be considered controlled
• Eligible for SABR
• Participants of child-bearing potential must agree to use adequate contraceptive methods (e.g., hormonal or barrier method of birth control; abstinence) prior to study entry. Should a woman become pregnant or suspect she is pregnant while she or her partner is participating in this study, she should inform her treating physician immediately
• Participant must understand the investigational nature of this study and sign an Independent Ethics Committee/Institutional Review Board approved written informed consent form prior to receiving any study related procedure

Exclusion Criteria:

• Patients with a history of a prior lung cancer will be excluded only if the previous treatment is within 6 months of the protocol therapy
• Mixed small cell and non-small cell lung cancer
• History of allogeneic organ transplantation
• History of primary immunodeficiency
• Patients must not have undergone prior radiation to overlapping regions of the chest that, in the opinion of the treatment physician, will interfere with protocol treatment
• Active autoimmune disease that has required systemic treatment in the last 2 years. Replacement therapy (e.g., thyroxine, insulin, or physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency) is not considered a form of systemic treatment and is allowed
• Known EGFR or ALK mutation
• Past medical history of interstitial lung disease (ILD), drug-induced ILD, radiation pneumonitis which required steroid treatment, or any evidence of clinically active ILD
• Pregnant or nursing female participant
• Unwilling or unable to follow protocol requirements