Short answer
Ads and trackers can follow you between apps through SDKs and analytics beacons baked into the apps themselves, not just inside your browser. Browser-based ad blockers and iOS App Tracking Transparency only see part of that picture, which is why the same ad can seem to chase you from a news app to a game to your email.
Why are ads following me from app to app?
Every app you use — a free game, a news reader, even a utility app — can embed tracking and ad SDKs that phone home independently of whatever you've set in Safari.
Browser content blockers have a limit: they only see traffic that passes through the browser. A tracker embedded in a non-browser app never crosses their field of view at all.
Where the tracking actually happens
The common thread is that tracking requests happen at the network layer — an app asks to connect to an ad or analytics server, and if nothing blocks that connection, the data goes out. Network-level filtering can block those connections across apps.
How Casper's Cloak closes that gap
Casper's Cloak filters at the network level across the whole device — iPhone, Mac, or Android — so the same filtering that blocks known tracker domains applies whether the request comes from Safari, a game, or a news app. It's the same underlying mechanism either way: a known tracking or ad domain, blocked before the connection completes, regardless of which app asked for it.
That extends filtering beyond a browser extension's browser-only view.
If ads and trackers chasing you between apps is the problem you're trying to solve, see how Casper's Cloak works or start a free trial.