Tumor suppression in humans relies on the immune system, but metastatic tumor cells can evade immune detection by using checkpoints like CTLA-4 and PD-1/PD-L1, thereby inhibiting immune responses and weakening anticancer immunity.This version simplifies and streamlines the information for better readability and clarity (Buchbinder and Desai, 2016; Qin et al., 2019). The gene discussed is CD274; the disease is neoplasm.