CD38 and neoplasm: TRM_2 is in part immunophenotypically similar to tumor-infiltrating cytotoxic CD38+ CD39+ CD4+ T cells observed in B7-H3 (CD276) knockdown (KD) tumors (Liu et al., 2023) and to a subset of T cells abundant in the gut mucosa of patients with CD and celiac disease expressing high levels of HLA-DR, CD161, and CD38 or CD39 (Bai et al., 2014; Christophersen et al., 2019; Mitsialis et al., 2020).