PDCD1 and glioblastoma: Further analyses of the paired pretreatment and posttreatment GBM revealed that the activated (PD-1+Ki-67+) tumor-infiltrating immune fraction increased 8.5-fold (from 5.2% to 44.2%) after neoadjuvant ICI therapy and was dominated by CD4+ TEM cells (65.3%), followed by CD8+ (21.5%) and Treg cells (12.4%; Fig. 2c,d).