Luoma and colleagues discovered that Treg cluster 1 cells were concentrated on colitis caused by anti–CTLA-4 monotherapy or in combination with anti–PD-1, expressing some genes specific to Th1 cells, such as IL-12 receptor and CXCR3, therefore revealing insufficient evidence of regulatory T-cell depletion in colitis (25). This evidence concerns the gene PDCD1 and colitis.