In iOS 14 Apple will give users the ability to block tracking. That part is great, but the dialog box is not needed since I can’t imagine any users will select yes to “Allow Tracking”.
Apple has delayed the rollout of this feature until 2021 after much complaining from large other tech firms with large advertising businesses.
https://www.bbc.com/news/technology-54033321
Facebook has weighed in that they will no longer be able to track users after they leave the facebook app, which is what user’s expect to be the default anyway.
https://www.facebook.com/business/news/preparing-our-partners-for-ios-14-launch