PDCD1 and glioblastoma: In this context, overactivation of ubiquitinoylation-related pathways such as neddylation, a post-translational modification process by which the ubiquitin-like protein NEDD8 is conjugated to its target proteins, and the simultaneous inhibition of PD-L1/PD-1 checkpoint by combined therapy, may be benefit in GBM patients by successful reverse of T cells maturation [41, 42].