A recent study in a cohort of glioblastoma patients treated with an anti-PD-1 mAb (nivolumab or pembrolizumab) upon recurrence revealed that a greater percentage of PTEN mutations is observed in non-responders (72%), as compared to responders (23%) and that PTEN-loss is also associated with a specific immunosuppressive signature. The gene discussed is PTEN; the disease is glioblastoma.