Some studies have suggested that PD-L1-positive tumors had prominent immune cell infiltration in CCA, such as CD3+ TILs (represent overall T cells), CD8+ TILs (represent cytotoxic T cells), and tumor-associated macrophages (TAMs) (CD68+, CD163+) (28, 31, 32). This evidence concerns the gene CD8A and cholangiocarcinoma.