In a small randomized phase II and biomarker study investigating anti-PD-1 plus bevacizumab for patients with recurrent GBM (n = 51), Nayak et al. reported that an increase in baseline placental growth factor and soluble VEGFR1 level, as well as post-therapy VEGF levels, correlated with poorer survival, suggesting a possible elevation in tumor hypoxia that leads to immunosuppression. Here, PDCD1 is linked to glioblastoma.