From reading the literature published so far studying cholangiocarcinoma and T lymphocytes, we can assume that regardless of CCA subtype, CD8+ and CD4+ T cells are mainly located in the peri-tumor area, and Foxp3+ T cells mainly infiltrate in the tumor center, but for some The contrary reports may be related to different sample sizes and research methods, so more research is needed to confirm. This evidence concerns the gene CD4 and cholangiocarcinoma.