PDCD1 and central nervous system cancer: Importantly, this ERG-based model not only stratifies glioma patients into high- and low-risk groups with distinct overall survival outcomes but also correlates with immune infiltration levels and the expression of multiple immune checkpoint genes, such as PDCD1, SIGLEC7, and LILRB2. This suggests that the ERG signature may reflect broader tumor-immune interactions, thereby contributing to both prognosis and treatment responsiveness.