That said, there are treaties covering IP that both the US and China are a party to which require certain mutual recognition. The US has sued China in the WTO for violating the IP provisions, but has not won most of those cases (AFAIK).
US companies can also sue Chinese companies in China for IP infringement and some of those cases have been won. Chinese courts tend to award much more limited damages than US courts, so US companies don't find this satisfactory. But again, that is a difference of law.