The long-rumored Oblivion remake is apparently very real indeed, and it'll pack plenty of visual and gameplay improvements, including changes to combat, the HUD, various gameplay systems, and more.
According to an MP1st report (which cites "a mistake made" by an ex-employee of support studio Virtuos), the remake of The Elder Scrolls IV: Oblivion will be built in Unreal Engine 5 and that it'll be a full remake rather than a simple remaster.
Supposedly, the website includes information regarding changes to certain gameplay systems. Blocking, for instance, will be more heavily inspired by Soulslike games thanks to the "boring" nature of shield-based combat in the original Oblivion, and sneaking will also be improved.

Other changes include a reworked stamina system that MP1st says will be less "frustrating" for players, as well as a new HUD that's "easier to understand and more aesthetically appealing to young players" (again, that's MP1st's wording, not the Virtuos employee's).
If you're wondering whether the unannounced project that's set to be revealed during next week's Xbox Developer Direct event is the Oblivion remake, MP1st says that's not the case, so don't expect a Bethesda announcement during that showcase.
However, as the MP1st report points out, rumors had already begun to swirl about an Oblivion remake potentially launching in June courtesy of insider NateTheHate, so if those rumors are correct, Microsoft likely won't want to wait too long to announce the project.
As ever, since there's no first-party source for this information, you should take it with a pinch of salt, but hopefully, we'll hear more about the Oblivion remake in the coming weeks.

If you somehow haven't heard of Oblivion, it's the fourth mainline entry in the Elder Scrolls series. Released in 2006, it's the precursor to the phenomenally popular Skyrim and the followup to the cult hit Morrowind.
A sixth Elder Scrolls game is in development at Bethesda right now, although it's been a very long time indeed since the project's official announcement. It is, according to an internal Microsoft document, set for release in "2026 or later".
You can pick up Oblivion right now on PC via Steam, although if these reports are correct, then you may want to hold off a little while as we wait for more info about the remake.