Apple and Google are cooperating (again!) on use of Bluetooth (again!) tracking technology. AirTags and other item trackers based on Bluetooth could be used to perform unwanted tracking.
Apple added additional safeguards to report unrecognized AirTag traveling with user. Also, app was introduced for Android users.
Now Apple and Google are working together to have unified specification to alert users of unwanted location trackers. Future versions of iOS and Android are to implement these specifications.
Apple Newsroom: Apple, Google partner on an industry specification to address unwanted tracking
IETF Datatracker: Detecting Unwanted Location Trackers
Google Play: Tracker Detect