The release date -- or more specifically the release window --- of the new Batman Arkham game may have just leaked alongside the game's reveal window. Back in September 2019, Warner Bros. Montreal confirmed and began to tease a new Batman game. However, not only have we not seen the game yet, but we haven't even heard anything about it since the turn of the year, or at least we haven't heard anything official. That said, it looks like that may change in the near future.
Prominent YouTuber, KnightWing01, recently revealed that he's heard the game will be revealed in August, which seems to suggest it will be revealed by itself and by Warner Bros. Interactive Entertainment. In fact, the YouTuber adds that he's head that Warner Bros. wants to be the one to reveal the game, which seems to rule out a Gamescom reveal in August or it making an appearance at the rumored PS5 event for August, which will allegedly reveal more games for the next-gen PlayStation console.
Adding to this, KnightWing01 mentions a November 2020 release window, which would be an incredibly quick turnaround from reveal to release, especially for such a huge release that would normally get a lengthy marketing campaign. However, it does line up with previous rumors and leaks suggesting the game will release this year, assuming it hasn't been delayed to due to COVID-19.
Of course, all of this should be taken with a major grain of salt. Nothing here is official, and everything is subject to change, especially during times like these. For what it's worth, I've heard the game won't be revealed at a PlayStation or Xbox event, but that's about all I've heard.
At the moment of publishing, neither Warner Bros. Montreal nor Warner Bros. Interactive Entertainment have commented on this latest report, and it's unlikely either will. Typically, publishers and developers don't comment on reports of this variety. However, if a comment is provided, the post will be updated.