The Protected Audience API (formerly known as FLEDGE) is a Privacy Sandbox proposal to serve remarketing and custom audience use cases, designed so third parties cannot track user browsing behavior across sites. This feature, Protected Audience Bidding & Auction Services, outlines a way to allow Protected Audience computation to take place on cloud servers in a Trusted Execution Environment, rather than running locally on a user's device. Moving computations to cloud servers can help optimize the Protected Audience auction, to free up computational cycles and network bandwidth for a device.
Explainers: https://github.com/WICG/turtledove/blob/main/FLEDGE_browser_bidding_and_auction_API.md https://github.com/privacysandbox/fledge-docs/blob/main/bidding_auction_services_api.md