According to the results, colony stimulating factor 1 receptor (CSF1R), hepatitis A virus cellular receptor 2 (HAVCR2), IL-10, PDCD1LG2, TGF-β1 as well as other immune checkpoint proteins or cytokines were almost positive correlated with FAP expression in different cancer types (Figure 8A), indicating that FAP may provide a vital help for immunosuppression. This evidence concerns the gene PDCD1LG2 and cancer.