TOX and neoplasm: TOX mRNA was elevated in CD8+ T cells when hyporesponsiveness was induced by a constitutively active version of NFAT1 (1), in CD8+ tumor-infiltrating lymphocytes (TILs) undergoing exhaustion (2), in mouse tumor antigen-specific CD8+ TILs or CD8+ CAR TILs (3, 4), and in exhausted TILs recovered from human melanomas (5).