CTLA4 and central nervous system cancer: In the present work, most of these exhaustion markers [TIGIT (Manieri et al., 2017), CEACAM1 (Huang et al., 2015), CTLA4 (Krummel and Allison, 1996; Postow et al., 2015), LAG3 (Ruffo et al., 2019), PD-1 (Ishida et al., 1992; Postow et al., 2015), PD-L1 (Postow et al., 2015), and TIM3 (Huang et al., 2015)] were highly expressed in the high-risk subtype (Figure 7A), indicating an elevated level of immune exhaustion in the tumors of high-risk glioma patients.