Apple's introduction of the async APIs means that we will have fewer reasons to use the Combine framework. Combine is still a great choice for reactive coding and - at least for now - async has no support for some of the delaying and throttling and other flow based niceties that Combine offers. Also, if you aren't ready to support iOS 15 or macOS 12 Monterey, Combine is still your choice.
But Combine will not have the position of prominence that Apple implied when they released it
That makes me sad.
I really like Combine and I really like the book I wrote about it. I've just gone through the book and updated it and it didn't need very much in the way of refreshing.
Because Combine is the pre-iOS 15 choice, I deliberately did not update the code to require iOS 15.
If you bought Combine or the Ultimate Bundle from Gumroad, the Combine update is free. If you don't own the Ultimate Bundle, you can upgrade to it and get credit for any books you've bought from Gumroad.
Update Combine Kickstart