CD274 and glioblastoma: Recent evidence has also shown that PD-L1 is expressed on glioblastoma EVs.151,152 Further, vascular heterogeneity exists, with vessel co-option (glioblastoma migration along existing blood vessels) occurring alongside angiogenesis, increasing the complexity of heterogeneity within glioblastoma.153 Further research into these factors, including utility of techniques such as single-cell RNA sequencing to characterise both tumour, and immune cell heterogeneity154,155 may facilitate a future shift towards more personalised treatment.