Among an array of available ICI strategies, blockade of programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) axis has achieved the most promising results in a variety of malignant tumors, including melanoma [6, 7], non-small cell lung cancer [8], renal cell carcinoma [9], and Hodgkin’s lymphoma [10]. This evidence concerns the gene PDCD1 and cancer.