Firstly, the expression of PD-L1 shows much heterogeneity of an individual, which might reflects the heterogenous expression of PD-L1 among cancerous cells in the primary tumor, the differenc of PD-L1 expression between the primary lesion and its metastases, and finally, the difference of PD-L1 expression of the tumor and its surrounding stoma cells, especially inflammatory cells such as lymphocytes and macrophages [33–36]. This evidence concerns the gene CD274 and neoplasm.