a, Representative flow plots of the cell surface phenotype of naive CD8+ splenocytes, progenitor exhausted TILs, or terminally exhausted TILs pre-stim (left) or after 40 hours co-culture with tumor cells (right) in the in vitro cytotoxicity assay (Supplementary Fig. 4d). b, Summary of the phenotype of tetramer+ sorted T cells after 40 hours co-culture with tumor cells. One of three independent experiments, n = 6 (progenitor exh.) or 21 (naive and terminally exh.) independent wells. c, Schema of experimental design for in vivo persistence and tumor assays. d, Summary of the phenotype of transferred progenitor exhausted cells harvested from spleen or tumors. Summary of two independent experiments, n = 9 (spleen) or 16 (tumor) mice post-transfer.