Early investigations in mouse models of solid and hematologic malignancies showed enhanced antitumor effects when treated with PD-1 or PD-L1 blockade in combination with in-field RT, sublethal total body irradiation (TBI), or stereotactic radiosurgery (SRS) compared to single modality treatment (Table 1) [69–85]. The gene discussed is PDCD1; the disease is hematologic disorder.