Please note: Take information such as this with a grain of salt until Capcom officially reveals Resident Evil 8.
Okay, so the little game is done. This will be breaking this month with more details later not by myself, but I've needed to clear some stuff up. "Resident Evil 2021" is Resident Evil 8, but it wasn't always RE8. During most of its development it existed as Revelations 3.— AestheticGamer aka Dusk Golem (@AestheticGamer1) April 4, 2020
According to the leak, the game was first designed as Resident Evil: Revelations 3. After great feedback from playtesters, Capcom decided to turn it into Resident Evil 8.
Dusk Golem further explained Resident Evil 8 will be taking some "serious departures" from the franchise. These thematic departures include occultism, hallucinations, insanity, and not being able to trust others.
From early playtester comments, it is suggested Resident Evil 8 will follow Ethan Winters (the protagonist from RE7). There will be werewolves, and Ethan was seen making his way through a snowy village.
Dusk Golem explained things might change since Capcom has decided to give the project more time to bake, rising into a full, mainline entry:
"The game has been going through some huge changes to make it more like a 'mainline' title, big changes to the story, characters, etc. So specifically what you've heard may not be fully true in the final, but a number of elements remain."
If the leak is accurate, then Resident Evil 8 is expected to release sometime in 2021. It should be a cross-gen title looking at the rumoured release window.
With supernatural elements and a first-person perspective, it remains to be seen how RE purists will react to the departures Resident Evil 8 is reportedly taking.