Dynamic changes in microbial composition are related to the progression of colorectal cancer (CRC); however, specific microbes with anti-CRC properties have not been identified. Here, we aimed to determine the effect of on CRC progression. In this study, the effect of was assessed in an azoxymethane (AOM)/dextran sulfate sodium salt (DSS)-induced CRC mouse model as well as in human CRC cell lines. Changes in anti-tumor immune responses were evaluated by flow cytometry. The functional metabolites produced by were identified by gas chromatography‒mass spectrometry (GC‒MS). The subcutaneously injected BALB/c mice with CT26 CRC cells were used to evaluate the effect of acetate produced by . We found that supplementation with suppressed CRC in an AOM/DSS-induced CRC mouse model as well as in the human CRC cell lines SW620 and HT-29. GC‒MS revealed that acetate is a functional tumor-suppressive metabolite produced by , and the tumor volume and tumor weight in the CRC model were inhibited by acetate administration. Mechanistically, produced acetate, which suppressed the expression of PDPN on CD8 T cells and that of C-type lectin-like receptor 2 (CLEC-2) on tumor cells. As a consequence, CD8 T-cell immunity was increased both and . In addition, we revealed that the acetate produced by can modulate podoplanin (PDPN)/CLEC-2/PI3K/AKT/mTOR signaling in CRC. In summary, produced acetate inhibits CRC by promoting CD8 T-cell immunity and modulating the PDPN-CLEC-2 pathway. Our data indicate that is a potential probiotic for cancer prevention and treatment.IMPORTANCEThis study identified as a novel probiotic that suppresses colorectal cancer (CRC) via acetate, which enhances CD8 T-cell immunity by blocking PDPN-CLEC-2 and induces tumor cell apoptosis through PI3K/AKT/mTOR pathway. These findings validated and acetate as dual-action therapeutic candidates through immune response activation and intrinsic tumor targeting by murine models and human CRC cell lines, thereby providing innovative strategies for CRC treatment.