KLRG1 and neoplasm: The SLECs PD1+ CD8 T cell population (KLRG-1+ / IL-7Rα-) that clonally expanded in response to the tumor was restricted to CD8 T cells co-expressing PD-1, as SLECs PD-1- CD8 T cells were almost undetectable in the tumor infiltrates of both HVEM WT and HVEM KO tumors (Figure 5A, lower panel).