DPP4 and neoplasm: •DDIT3 supports tumor growth by regulating extracellular matrix remodeling and growth factor secretion.•CAFs exhibit significant heterogeneity; Detox-iCAF may transform into other subtypes via DPP4 and YAP1/TEAD signaling.•mCAF enriches fatty acid synthesis, pCAF enriches the TCA cycle, and meCAF enriches glycolysis and amino acid metabolism.•iCAF co-localizes with CD8+ T cells, promoting an immunosuppressive TME.