A leak has surfaced on Reddit that claims a sequel to Marvel's Spider-Man is in the works and may release "Holiday 2021." Reddit user v17447377 posted the leak which claims to be from a source "close to Insomniac games" listed story content and features that are said to be in the game alongside the 2021 release date window.
According to the leak, our reunion with Peter Parker will take place in another open world Manhattan area that has expanded from the first game to include Queens and Brooklyn. The leak also claims that it takes place over the winter time, as well as the reddit post goes on to detail some "sparse" story details. Oscorp is said to play a major role in the sequel, with mentions of cloning and nods towards the Marvel Universe outside of Spider-Man's web.
The post ends with the claim that Insomniac is doing "major engine work" and "adopting more technological advances" such as photogrammetry. If the sequel is in development, the release date window would likely place it on the PS5, Sony's upcoming next-gen console slated for release at the end of this year.
There's little evidence to back up this leak and there's every chance these are a series of educated guess. The Reddit user in who announced this leake also recently posted a leak that claimed the (now confirmed) Resident Evil 3 Remake was on the way ahead of Capcom's official announcement.
We'll just have to wait for official confirmation to see how accurate this leak is.