Key Inclusion Criteria:

          1. Age ≥18 years

          2. Histologically or cytologically documented Stage I to II NSCLC, with clinical Stage
             I/II lymph node-negative (T1 to T3N0M0) disease and planned to receive definitive
             treatment with SBRT. Patients may be medically inoperable or are medically operable
             and refusing surgery or choosing to have SBRT (Stereotactic Body Radiation Therapy) as
             definitive therapy

          3. Planned SoC SBRT as definitive treatment

          4. World Health Organization (WHO)/Eastern Cooperative Oncology Group (ECOG) PS of 0, 1,
             or 2

          5. Life expectancy of at least 12 weeks

          6. Body weight >30 kg

          7. Submission of available tumor tissue sample

          8. Adequate organ and marrow function required

          9. Patients with central or peripheral lesions are eligible

         10. Staging studies must be done within 10 weeks before randomization

         11. Patients with a history of metachronus stage I/II (T1-T3N0M0) NSCLC treated
             definitively surgery only or SBRT only >1 year prior to enrollment are eligible.

        Key Exclusion Criteria:

          1. Mixed small cell and non-small cell cancer

          2. History of allogeneic organ transplantation

          3. History of another primary malignancy with exceptions

          4. History of active primary immunodeficiency