A recent study shows that DCA concentration negatively correlates with CD8+ T cell function in colorectal cancer (CRC) patients, with DCA suppressing CD8+ T cell responses by targeting plasma membrane Ca2+ ATPase (PMCA) to inhibit Ca2+-NFAT2 signaling.7 This effect can be abolished by the ablation of bacterial DCA biosynthetic pathways.7 Moreover, microbial BAs can alter tumor cells to regulate CD8+ T cell responses in antitumor immunity. Here, CD8A is linked to colorectal carcinoma.