PDCD1 and cancer: Because most patients with cancers cannot benefit from PD‐1/PD‐L1 immunotherapy due to congenital or acquired resistance, there is a need to identify target genes that can be mutually regulated with PD‐1/PD‐L1 to improve the benefit rate of clinical immunotherapy, and we suspect that CKLF may play the above‐described regulatory role, but this needs to be confirmed by further experiments.