CD4 and cancer: Interestingly, there was slightly more clonal overlap between TRM_2 and other CD4+ T cell subsets in control samples, possibly reflecting clonal proliferation of T cells in the peri-cancer region (albeit pathologically normal mucosa), supporting the previous findings that tumor-infiltrating lymphocyte clones are also clonally expanded in adjacent nontumorous tissues (Penter et al., 2019) (Fig. 3, A–C; and Fig. S2 A).