Non-small cell lung cancer (NSCLC) is a common and lethal malignancy. The recent development of immune checkpoint inhibitors has afforded a durable, dramatic treatment response for a subset of patients, but strategies to expand these benefits to a broader swath of patients are needed. Preliminary evidence suggests radiotherapy may modulate a patient’s immune system, particularly when delivered in high doses over few fractions with conformal techniques, as with stereotactic ablative radiotherapy (SABR). Radiotherapy for advanced stage NSCLC has traditionally been administered with palliative intent. However, an emergence of data from retrospective studies and, more recently, prospective trials has indicated the potential of using stereotactic ablative radiotherapy (SABR), in combination with systemic immunotherapy agents have synergistic effect and may enhance survival. We review current evidence for synergy between radiation and immunotherapy in metastatic, locally advanced, and localized NSCLC and discuss ongoing studies.Copyright © 2020. Published by Elsevier Ltd.