Even if the progress has been promising with the advent of various targeted therapies and the application of immunotherapy, such as the great achievements in the use of programmed cell death protein-1 (PD-1) and programmed cell death legand-1 (PD-L1) over the past several years, the incidence and mortality have ranked first among all malignant tumors, and the prognosis is still poor [2]. Here, PDCD1 is linked to cancer.