Immunotherapy SBRT Sensitization of the Programmed Death-1 (PD-1) Effect

Inclusion Criteria: * Histologically or cytologically confirmed Stage IV NSCLC according to the 7th AJCC staging manual. * Eligible for an immunotherapy agent. Patients who progress after drug therapy (3 months) for ALK, EGFR or ROS mutation positive lung cancer are eligible. * At least 2 lesions that are safely amenable to SBRT. ECOG \<=2. * At least 1 measurable lesion according to Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria for response assessment or at least 1 lesion with FDG avidity and CT correlate that can be monitored for PET-CT response by SUV Max increase or decrease. * Normal Hepatic and renal function. * Bone marrow reserve: 1. ANC ≥ 1.5 x 109/L 2. Hemoglobin ≥9.0 g/dL 3. Platelet count ≥75 x 109/L * Ability to comply with follow-up visits and evaluations, treatment planning and studies and other study related procedures and visits. * Ability to sign informed consent. Exclusion Criteria: * Patients with active CNS metastases * Active, known or suspected auto-immune disease. * Patients with medical conditions that require systemic immunosuppression. * Patients with a history of interstitial lung disease. * Prior treatment with immune checkpoint inhibitors/immonotherapy. * Other active malignancy requiring intervention. * Prior lung radiation, with the only metastatic targets in the lungs. * Unresolved toxicity from prior chemotherapy or anti-cancer treatment. * Current or prior enrollment in clinical trial with an investigational drug within 4 weeks. * Pregnancy or positive pregnancy test.