It's not confirmed what it is yet, but Capcom still apparently has an "unannounced major title" due out before March 2024.
As spotted by a user on the GamingLeaksAndRumours subreddit, Capcom recently shared a document covering a Q&A following its latest earnings results, where it referred to said "unannounced major title." The game came up following a question of how it plans to achieve its sales goals for new titles this fiscal year, noting the upcoming Apollo Justice: Ace Attorney Trilogy, as well as whatever this game might be. Capcom is certainly cutting it a bit close with announcing the thing, though, as March is barely five months away now.
Obviously the big thing here is that Capcom's fiscal year ends in March, and it will have already set out these goals, so it's likely a thing of "don't worry, you'll make your money before the year is up." Aside from hosting its own showcase, which Capcom has done in the past, the most likely place we'll hear any kind of announcement would be The Game Awards in December, though that does feel like it would be cutting it especially close.
Unsurprisingly, a number of users in the comments of the Reddit post were speculating a new Monster Hunter game, which does feel like the series that fits the moniker of "major title" the best. The most recent entry in the series, Monster Hunter Rise, originally released on Nintendo Switch, and while it did receive a PlayStation and Xbox release earlier this year, the current generation of consoles doesn't have a Monster Hunter game it can really call its own.
A new Resident Evil game also feels unlikely given the release of the Resident Evil 4 remake earlier this year, and Dragon's Dogma 2 likely won't release until later in 2024. And it won't be the mysterious Pragmata either, as that's been delayed indefinitely. But hey, there's always a chance for a big new Mega Man right? Right?