Here, we found that Loxoribin, one of the TLR7 ligands, could inhibit tumor growth in xenograft models of colon cancer and lung cancer, and these anti-tumor effects of Loxoribin were mediated by promoting CD4+T cell proliferation and reversing Treg-mediated suppression via dendritic cells (DCs). Here, TLR7 is linked to malignant colon neoplasm.