IL6 and neoplasm: Mechanistically, CAFs remodel ECM to create physical and biochemical barriers to drug delivery and immune infiltration, secrete cytokines and growth factors (such as IL-6, SDF-1, periostin) that foster immunosuppression and angiogenesis, and undergo metabolic reprogramming themselves—enhanced glycolysis, increased glutamine or lipid utilisation—to sustain tumour growth and modulate the immune-metabolic microenvironment (85).