Among them, ICBs such as PD-1, PD-L1, and CTLA-4 inhibitors have been reported to exert optimal therapeutic effects in various malignant tumors with a lower frequency of adverse events than conventional therapy such as chemotherapy, especially for the treatment of melanoma, bladder cancer, lung cancer, and hematopoietic malignancies (35-, , 38). This evidence concerns the gene CTLA4 and cancer.