PDCD1 and cancer: Of 126 cancer patients receiving PD-1 inhibitors and RT, 53% (67/126) of patients were treated simultaneously, and 36% (24/67) patients met the inclusion criteria, that is, RT started within one month of the first or last application of PD-1 inhibitors (pembrolizumab or nivolumab) and at least one metastasis lesion outside the 10% iso-dose range of the prescribed radiation dose.