From a user perspective, it has been recommended as a good practice to make use of a .cn domain in China, as it indicates a “locality” for the website, but it is by no means a requirement.
.com domains rank as well as .cn and .com.cn domains within Baidu search results.
Are .cn domain TLDs a ranking factor in Baidu?
Anecdotally evidence suggests that a .cn is not required to rank well within Baidu.
However, in my opinion, if you’re in a niche that requires trust (such as personal finances) and deals with older demographics (perhaps 50+), then a .cn or .com.cn domain can help with user acceptance of your brand.
Also if you have an established brand, and already receive traffic from the Chinese market (and you’re using a .com or .net), then it doesn’t make sense to introduce a brand new domain into the mix – especially when Baidu doesn’t respect Hreflang, so you will need to block Baidu from crawling your non-Chinese domain and lose a lot of link equity/brand benefit.