TikTok’s iOS app uses in-app browser to log your keystrokes and taps
When you open any link on the TikTok iOS app, it's opened inside their in-app browser. While you are interacting with the website, TikTok subscribes to all keyboard inputs (including passwords, credit card information, etc.) and every tap on the screen, like which buttons and links you click.
TikTok is spyware, and should be labelled and treated as such.