Moreover, tumor immunotherapy is in the ascendant, encouraging us to start a new era of cancer treatment, mainly including programmed cell death 1 (PD-1) and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) checkpoint inhibitors (Sangro et al., 2013; Chang Lee and Tebbutt, 2019). The gene discussed is CTLA4; the disease is cancer.