Radiation is an essential tool in cancer therapy, both in the definitive and palliative setting. Radiation therapy can drive the cancer immune cycle via several mechanisms, but it also has immune suppressive effects that might be overcome via radiation/immunotherapy combination approaches. Understanding this underlying biology will lead to improved combination therapy approaches. Although clinical evidence of radiation and immunotherapy combination approaches in the metastatic setting to induce an abscopal response is limited, combination approaches in the oligometastatic and definitive setting are extremely promising.