CD274 and glioma: According to the Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA) database, a high expression of both PD-L1 and PD-1 negatively correlates with prognosis of patients (p = 0.0031 and p = 0.0253, respectively) [9,10]; however, in other studies [11,12], no significant correlations were reported.