That speculation may partly derive from previous reports suggesting Xbox was working on a Halo: Combat Evolved remaster for the Sony platform, but still, the topic is out there and folks are talking about it. Heck, Digital Foundry has also suggested the PS5 possibility in a recent article on the series' UE5 switch.
But, do you think this is a move in that direction? Could Halo really go to PS5? Honestly, that's such a crazy thought that we're still processing it - and have been ever since that Halo remaster rumor. For clarity's sake, here's how DF suggested the move in its discussion on the matter:
"From a multi-platform game development perspective, moving to Unreal Engine 5 would certainly be easier for the developer than porting across the existing Slipspace engine,
It stands to reason that an engine designed for deployment across multiple platforms would be easier to work with than existing technology built for Xbox and PC."
The article also mentions that the old Slipspace engine could have been deployed on PS5 of course, and any suggestions that this Unreal switch is to enable PS5 development is pure conjecture at this point. Microsoft and the Halo team seem to have plenty of other reasons for ditching the old engine.
Of course, fans on the other side of the fence have also begun speculating about this - we're sure PlayStation players would be eager to get a hold of Xbox's flagship franchise on PS5.