Big progress has been made in tumor immunotherapy recently by the utilization of immune checkpoint inhibitors (ICIs), including anti-PD-L1/PD-1 2-4 and anti-CTLA-4 5-7 antibodies, to overcome the tumor immunosuppressive environment, which shows clinical efficacy in the treatment of various cancers including melanoma, ovarian cancer, colorectal cancer and lung cancer 8, 9. This evidence concerns the gene CTLA4 and neoplasm.