TGFB1 and melanoma: Functional validation showed that ETV5 knockdown reduced melanoma-cell migration and proliferation and promoted apoptosis.<h4>Conclusion</h4>Our integrative single-cell analysis identifies C3 ID4<sup>+</sup> TCs as a critical driver of melanoma progression, associated with metabolic reprogramming, immune evasion, and TGF-β-related intercellular crosstalk.