Developers use trackers to identify each user in different apps and websites so they can target advertisements based on what you access on your device. Even if users leave this option enabled, third-party apps will have to ask permission for tracking and collecting your personal data.
CNBC
Facebook is now upset among other ad publishers for iOS 14’s new feature that blocks trackers left on a device. It is amazing how kicking in a bit of privacy could impact a bottom line when it fully rolls out later this year.