CD226 and glioblastoma: Through systematic evaluation of anti‐glioma activity, biosafety, and SAR analysis, we identified B7 (2‐(2‐methylbenzyl)‐4‐(2,4,4‐trimethylpentan‐2‐yl)phenol) as a BBB‐permeable lead candidate that demonstrated significant anti‐GBM effects with dual‐mode anti‐GSC mechanisms that directly suppressed GSCs while concurrently activated NK cell‐mediated immunity via the CD155/TIGIT/CD226 immune checkpoint axis within the TIME, mechanically distinct from its parent compound CFT.