Blizzard is currently working on bringing their games to the Steam store, abandoning their exclusive strategy on Battle.net. Overwatch 2's Steam page is now up, showing the game supports Traditional Chinese but not Simplified Chinese.
Overwatch 2 Steam Store Page
Overwatch 2 Language Supports
As part of Blizzard's plan to bring their games to Steam, Overwatch 2 will be released on the Steam platform on August 11th.
Overwatch 2 on Steam
Source: Steam