The possible reasons might be as follows: (1) the methods and antibodies used for IHC to detect the PD-L1 level vary from different clinical studies; (2) the scoring system determining the quantification of PD-L1 expression of tumor cells, tumor-infiltrating immune cells, or both, is not consistent and it is difficult to confirm the best cutoff value; and (3) the expression of PD-L1 suffers from heterogeneity in space and time. Here, CD274 is linked to neoplasm.