A sad day for those hoping for full backwards compatibility.
PlayStation 5

According to a new support page from Ubisoft, it appears that PlayStation, PS2, and PS3 games will not be backwards compatible on the PlayStation 5. This support page was put up to help users address the transition from this current-gen to next-gen platforms.

They put it up in very clear terms.

Backwards compatibility will be available for supported PlayStation 4 titles, but will not be possible for PlayStation 3, PlayStation 2, or PlayStation games.
Sony has said for a while now that the PlayStation 5 would be backwards compatible with most PlayStation 4 titles. However, they would often shy away from talking about backwards compatibility with their older platforms. I guess there is a reason the company chose not to say anything more on that front. Even with their PS4 backwards compatibility, Sony has not promised full support for all PS4 titles. Right now it's an ambiguous "overwhelming majority of the 4,000+ PS4 titles will be playable on PS5."

Meanwhile, Microsoft has already committed to offering backwards compatibility for the Xbox Series X that will see support for Xbox, Xbox 360, and Xbox One titles. However, full backwards compatibility may not be possible on the Series X either, though Microsoft has promised that Series X will be able to play "thousands" of those older titles.

There was still hope that Sony was working on something similar for the PlayStation 5, but Ubisoft's support page may have put the final nail in that coffin.