In KEYNOTE-051, pembrolizumab showed some benefit in paediatric patients with various PD-L1+ solid tumours, including partial response in a patient with a malignant ganglioglioma, and tumour shrinkage (< 30% decrease) in patients with high-grade glioma, glioblastoma, ependymoma, and ganglioneuroblastoma among other tumours [3]. The gene discussed is CD274; the disease is glioma.