However, besides cancer cells, TAM are the predominant cells that express PD-L1 within human tumors, and in some cancers, such as hepatocellular carcinoma (HCC), ovarian small cell carcinoma, and breast cancer, the expression level of PD-L1 in TAM is higher than that in tumor cells [85,86,87]. The gene discussed is CD274; the disease is hepatocellular carcinoma.