Recent studies based on single-cell technologies have revealed functional and spatial heterogeneity within the progenitor Tex cell subset: in chronic infections, a precursor subset marked by high expression of CD62L [98] or CD69 [99] is thought to give rise to progenitor Tex cells, while stem-like CD8+ T cells residing in draining lymph nodes may be precursors of progenitor Tex cells in the tumor microenvironment [100–102] (Fig. 2B). This evidence concerns the gene CD8A and neoplasm.