Several studies have shown that PD-L1 glycosylation exists on the surface of various types of cancer cells (including lung cancer, melanoma, and breast cancer), which affects the structure and function of proteins and causes their polypeptide antigens to be unable to be recognized by PD-L1 antibodies, affecting the immunohistochemical detection of specimens and leading to abnormal results [36]. This evidence concerns the gene CD274 and cancer.