China does not need to negotiate with a bully. US firms will be pleading with Trump to relent.
Russia also recognise this. They continue the war despite trumps interference. No point dealing with the US. Any agreement signed are not iron clad. US at a whim can just walk out and revoke.
Iran should just build the nuclear bomb. Don't waste time negotiating with the US. Look what US did last time there was a agreement, signed and sealed. If no nuclear bomb, US going to bomb Iran anyway.