CD274 and hepatocellular carcinoma: In this case, we observed dynamic alterations of PD-L1 expression and cytotoxic T cells, i.e., some infiltrated cytotoxic T cells and negative PD-L1 expression in the primary and, on the contrary, few T cells but expressed PD-L1 in the relapsed HCC lesions after sintilimab treatment, which implied heterogeneous microenvironments between the primary tumor and its metastasis in this case.