Apple's blog post about their plans: "We are committed to ensuring users can choose whether or not they allow an app to track them. To give developers time to make necessary changes, apps will be required to obtain permission to track users starting early next year. More information, including an update to the App Store Review Guidelines, will follow this fall." https://developer.apple.com/news/?id=hx9s63c5
This reads as just another popup you'll need to click before you can use any app. Just like cookies.
With GDPR cookie warnings, you’re required to opt in, but everybody uses dark UI patterns to make you “opt in” (like forcing you to uncheck each tracker individually, and claiming it takes several minutes to “update your preferences”)