Specifically, correlation analysis of MSI with tumor-infiltrating immune cells, MHC I, and PD-L1 expression showed a high number of CD8+ T-cells, FOXP3+ regulatory T-cells, CD20+ B cells, and high MHC I expression in MSI-H CCAs, suggesting that these parameters could be correlated with better OS in CCA treated with immunotherapy [28]. This evidence concerns the gene FOXP3 and cholangiocarcinoma.