What happened to iTunes?

There is no iTunes app in macOS Sonoma, not since Catalina. See: What happened to iTunes? - Apple Support there’s now an App for each Media type instead. Music can be found in The Music App. Movies, tv shows in Apple tv App, and so on. There’s still an iTunes Store.

Ybrown wrote:

What happened to iTunes?

I keep getting "this applications requires iTunes" butI can't find it any more...

Where are you seeing this message? If possible post a screenshot.