Listening to the latest Dithering podcast with John Gruber and Ben Thompson, Ben noted that Apple traditionally only has executives "on stage" at the WWDC keynote if they have something to present. As John Ternus is still Senior VP of Hardware Engineering, he would be present only if there were new Macs to announce. And yet, as the next CEO of Apple, you are going to want him presenting during the keynote.
So I think Apple could pull a page from the Mac Pro playbook and announce the Mac Studio with M5 Max and M5 Ultra, but note it will not ship until the end of the year. They might also announce the Mac mini with the same caveat.