PDCD1 and type 1 diabetes mellitus: These cells were characterized by expression of Cxcr6, Pdcd1, Tigit, and Eomes and were reminiscent of both CXCR6+ PD-1hi exhausted CD8 T cells from LCMV Cl13 infection (Zander et al, 2019) as well as TIGIT+ Eomeshi CD8 T cells found in the peripheral blood of T1D patients (Wiedeman et al, 2020).