First, we confirmed that CD4+ T cells in transplanted B16-3340 tumors or the tumor-draining lymph node (TdLN) do not produce IL-17A, unlike cells from the small intestine, by using IL-17A-GFP reporter mice colonized with SFB and treated with anti-PD-1 antibody (Extended Data Fig. 7a). This evidence concerns the gene CD4 and neoplasm.