Spearman’s correlation analysis of immune subpopulations applied in the TCGA-GBM cohort revealed a negative correlation between mRNA PTEN mutations expression (log2 TPM) and infiltrating T cell CD4+ Th 1 (ρ = −0.245; p = 3.81 × 10−3), Th 2 (ρ = −0.225, p = 8.06 × 10−3), and NK cells (ρ = −0.163, p = 5.64 × 10−2) within the tumor microenvironment. The gene discussed is PTEN; the disease is glioblastoma.