In this study, we found that Loxoribin, one of the TLR7 ligands, could inhibit tumor growth in vivo in both colon cancer and lung cancer xenograft models, and these antitumor effects of Loxoribin were mediated by promoting CD4+T cell proliferation and reversing Treg-mediated suppression via DCs. The gene discussed is TLR7; the disease is lung cancer.