Subsequently, scientists discovered key immune checkpoint molecules involved in tumor immune evasion, including cytotoxic T‐lymphocyte‐associated antigen 4 (CTLA‐4) and programmed cell death protein 1 (PD‐1), which led to the development of a series of immune checkpoint inhibitors (ICIs) [9, 10, 11, 12, 13, 14]. The gene discussed is PDCD1; the disease is neoplasm.