Microbially derived indoles (indole, indole-3-acetic acid/IAA, indole-3-propionic acid/IPA, indole-3-lactic acid/ILA) critically influence CRC progression: ILA—the most extensively studied anticancer indole—activates CD8+ T cells by enhancing dendritic cell IL-12 production via histone modification and chromatin accessibility (316), promotes effector molecule release by inhibiting the cholesterol metabolism gene Saa3 in CD8+ T cells (316), and reduces CD86+ proinflammatory macrophages via AhR/p-AKT/IL-1β signaling (374). Here, CD8A is linked to colorectal carcinoma.