Tumor cells can also express PD-L1 as an adaptive immune mechanism to evade antitumor immunity [19]. The PD-1/PD-L1 pathway plays a crucial role in regulating T-cell activation, proliferation, and cytotoxic secretion in cancer, and PD-1/PD-L1 inhibitors demonstrated significant therapeutic efficacy across many cancers [20]. This evidence concerns the gene PDCD1 and cancer.