It should be emphasised that whole-body 18F-AlF-NOTA-ZPD-L1 and 68Ga-NOTA-ZPD-L1 PET will not distinguish between the different types of cells expressing PD-L1, including GBM cells and immune cells (e.g., T cells, macrophages, dendritic cells and neutrophils). Here, CD274 is linked to glioblastoma.