CXCL12 and lung cancer: Early researchers reported that CXCR4 expression in lung cancer could serve as a marker of cancer‐initiating cells and be associated with poor clinical outcomes.[35] In pancreatic ductal adenocarcinoma, high levels of CXCL12 expressed by carcinoma‐associated fibroblasts (CAFs) lead to immunosuppression and T‐cell dysfunction.[36] However, other investigators have shown the antitumor effect of the CXCL12/CXCR4 axis.