Backwards compatibility rumors concerning the PlayStation 5 are back, with full PS3 emulation supposedly on the cards. Sony's new PlayStation Plus service will offer playing of PS3 titles on the PS5 via cloud streaming, but it will be at the mercy of the console owner's internet connection speed.
https://www.notebookcheck.net/PlayStation-3-emulation-likely-heading-to-the-PS5-but-might-take-some-time.611551.0.html