MKI67 and neoplasm: Also in YUMMER1.7 tumors, TILs from mice lacking Il23r in Treg cells, albeit not increased in number (Extended Data Fig. 3d,e), displayed a highly activated signature reflected by the expression of CD44, CD25, CD69 and Ki-67 and the transcription factors TCF-1 and TOX (Extended Data Fig. 3f), which mark CD8+ tumor-specific T cells transitioning toward an intermediate dysfunctional stage28.