This will be more similar to giving location or push permissions that a cookie warning. You have to actively opt-in to allowing an app access to your IDFA on an

This will be more similar to giving location or push permissions that a cookie warning. You have to actively opt-in to allowing an app access to your IDFA on an app-by-app basis. They can ask you to do this one time and if you say no the only way that setting will ever change is if you go to the iOS settings app and enable tracking for that app. Currently you can opt out on a system level. The change will make it opt in on an app level.