Interestingly, the levels of PD-L1 expression in tumor cells were lower or even undetectable in glioblastoma patients who exhibited longer survival following T cell therapy against CMV, suggesting that inhibition of the PD-1/PD-L1 pathway may be a promising treatment strategy, especially when combined with CMV-specific adoptive T cell therapy in glioblastoma patients. This evidence concerns the gene PDCD1 and neoplasm.