If you're interested in the legal details behind the deal, AnandTech has plenty of coverage in its review of the Hygon Dhyana x86 processors, which you can check out over here. The site managed to get it hands on two parts, the 8-core Dhyana and Dual 32-core Dhyana Plus.
Tests reveal these processors differ from the Zen 1 design in a number of ways. They offer roughly the same integer performance, but floating point performance is much worse. Similarly, random number generation is slower and of lower quality, and the cryptographic engines have been replaced to better suit Chinese security standards like SM2, SM3, and SM4.
However, as AnandTech reports, the Hygon Dhyana x86 processor project is now essentially dead due to the trade war between the US and China. The deal was also only for a single design and it's very unlikely that AMD will enter something similar as the company is no longer strapped for cash.
Overall these Hygon CPUs offered China an alternative to the Intel market, and arguably something faster than they might have been able to purchase through import restrictions. AMD made some money at a time it badly needed it, but with the success of its Zen 2 platform, I don’t foresee AMD needing to do something similar over the next decade. The nature of the agreement between AMD, its joint venture THATIC, and the joint companies, was only for a single core design, Zen 1, and not Zen 2, limiting its competitiveness. Moreover, the US Entity List ban on one of the joint venture companies, for all intents and purposes, has made the project dead. The Chinese Hygon Dhyana x86 processors will still be in use by governments and other such organizations for a number of years to come, but this is bound to end up one of the oddest annals of the history of semiconductors.