CTLA4 and neoplasm: This exhausted state is correlated with upregulation of multiple cell surface inhibitory receptors, including PD-1, LAG3, and CTLA4.(52) CD8+ T cells from tumor-bearing mice exhibited high surface expression of PD-1, whereas CD8+ T cells from Ace-Blank and Ace-Resi mice did not (Fig. 4E–F).