Beginning on this date, all new Teams customers in South Korea (e.g., new tenants, or first use of Teams) will be served out of the South Korea data centre. For these new customers, files uploaded to a Teams channel will be stored in SharePoint Online in-country, and files uploaded through 1:1 chat will be stored in OneDrive for Business in-country.
For existing customers, customer data in Teams continue to be stored in its current location.
Exchange Online, SharePoint Online, and OneDrive for Business also provide customer data residency in South Korea.
Image from Wikipedia.
Microsoft also noted in the blog “Our goal is to provide data residency for Teams in all the Office 365 country-based datacenters”. So we can likely expect more coming in the future.