Various factors have been shown to increase the risk of CIP, including use of PD-1/PD-L1 agents (52, 53) (compared with CTLA-4 inhibitors), combination immunotherapy (54, 55) (CTLA-4 and PD-1 combination rather than monotherapy), radiotherapy (56, 57), and the organ of tumor origin (58, 59) (e.g., NSCLC vs. renal cell or other cancer types). Here, PDCD1 is linked to cancer.