Additionally, MSI-high colorectal cancer is more sensitive to immune checkpoint inhibitor (ICI) therapy, while MSS tumors largely remain unresponsive.46 The reasons behind this selective responsiveness are believed to be associated with the high mutational burden and heightened levels of tumor-infiltrating lymphocytes inherent to CRC MSI-high tumors.46 In the current study, we find that, in addition to the downregulation of DNA mismatch repair genes, PD-L1 (CD274) is upregulated, which indicates that ADP-heptose could promote an immune-suppressive tumor microenvironment. Here, CD274 is linked to colorectal cancer.