CXCL12 and pancreatic ductal adenocarcinoma: In pancreatic ductal adenocarcinoma (PDAC), CXCL12 produced by FAP+ CAFs coats tumor cells and excludes T cells; CXCR4 blockade (AMD3100) disrupts this barrier, permits intratumoral CD8+ accumulation, and synergizes with anti-PD-L1 [154].