KLRB1 and neoplasm: Tscm cells, which appear to be contained in cluster 8.6 (KLRB1) on the basis of signature gene expression, have the capacity for self-renewal and to differentiate into memory and effector cells, thereby acting as a “resource” cell to replenish tumor-reactive CD8+ T cells (Brummelman et al., 2018; Gattinoni et al., 2011; Im et al., 2016; Miller et al., 2019; Siddiqui et al., 2019).