OAuth 2.0 Token Exchange is an extension to the standard OAuth 2.0 protocol. It enables client applications to request and obtain security tokens (such as access tokens) from an authorization server (in this case, Cloudentity) acting as a Security Token Service (STS).

https://cloudentity.com/developers/basics/oauth-grant-types/token-exchange/#:~:text=OAuth%202.0%20Token%20Exchange%20is%20an%20extension%20to%20the%20standard,Security%20Token%20Service%20(STS).