Glioblastoma is one of the deadliest forms of brain cancer, known for rapid growth, resistance to treatment, and frequent relapse. In this study, researchers explored a novel approach: whether early exposure to CBD could “prime” the body’s immune and molecular environment in a way that makes it less hospitable to tumor growth. After tumor implantation, researchers measured tumor growth and analyzed several biomarkers associated with tumor aggressiveness and immune suppression, including IDO, PD-L1, MGMT, and Ki67. Mice that received 14 days of CBD pretreatment had significantly smaller tumor burdens compared to both the placebo group and the group that received CBD for only three days. In addition, the CBD-pretreated mice showed lower levels of MGMT and Ki67, biomarkers associated with tumor growth, repair capacity, and proliferation.