Radiotherapy has known immunomodulatory effects and there exists a strong preclinical rationale for combining radiotherapy with immunotherapies. Broadly, the concurrent administration of immunotherapies and radiotherapy does not seem to result in undue toxicity, even when radiotherapy is administered to definitive doses. Recently reported results from prospective clinical trials evaluating radiotherapy/ICB combinations, such as the PACIFIC trial, provide important information on safety and efficacy in the definitive setting and identify potential abscopal effects. This review details the preclinical foundation for the combination of radiotherapy and immunotherapies, summarizes the most recent clinical data available, and highlights active and future areas of study.