Yes, you can install Pop!_OS's shell inside Zorin OS, but keep in mind that this is the implementation for Gnome, not the upcoming Cosmic desktop environment.
You can find instructions here:
I just noticed I messed up badly in writing those instructions. Where I say:
-Download the appropriate branch of the pop-shell repository. Since ZorinOS 16 is based off of Ubuntu 20.04, you need to use the Jammy branch:
+Download the appropriate branch of the pop-shell repository. Since ZorinOS 16 is based off of Ubuntu 20.04, you need to use the Focal branch:
The steps are the same, you just need to pay attention to which branch you're installing. Use the branches master_focal or master_jammy for Zorin OS 16 and 17, respectively.
There are no announcements made about this. If it does happen, it will probably take a while and will be announced with enough time ahead. Keep in mind that it's still early days for Cosmic and there are plenty of things that aren't ready for production.