CXCL12 and neoplasm: CXCR4 inhibitors (e.g., plerixafor, motixafortide) disrupt the CXCR4–CXCL12 axis, inhibiting tumor cell homing, metastasis, and immunosuppression, with clinical trials (NCT02826486, NCT03168139) showing improved T cell responses and synergy with anti-PD-1/PD-L1 therapies in metastatic PDAC (96, 113, 114).