The PD-1/PD-L1 checkpoint axis possesses both beneficial and harmful properties, e.g., it confers immunosuppressive protection in autoimmune diseases, whereas in cancers and fibrotic diseases it provides an immune escape mechanism for abnormal cells to avoid immunosurveillance (Francisco et al. 2010; Toor et al. 2020; Zhao et al. 2023). This evidence concerns the gene PDCD1 and cancer.