CXCL12 and cancer: A recent atlas of ~50,000 single cells and 16,000 spatial barcodes reconstructed whole-tumour volumes at 50-μm isotropic resolution and identified a hierarchically layered immune topology: (i) an inner necrotic core infiltrated by C1QC+/LGALS3+ macrophages and VEGFA+ endothelial networks, (ii) an intermediate osteolytic belt enriched for PD-L1 high RUNX2+ osteoblast-like tumour cells, and (iii) an outer peri-vascular rim populated by CXCL12+ cancer-associated fibroblasts that ‘wall off’ T and NK cells (28).