
Ok, it's happening, everybody stay calm: Resident Evil Requiem's producer Masato Kumazawa has said that characters from past series will be making an appearance in the next Resi game, which means the possibility of Leon Kennedy showing up has just skyrocketed.
"I would say that yes, there are going to be some characters from the past series to come in, but don’t over-expect or hype it," Kumazawa says in an interview with Well-Played (via IGN). "We can’t promise you anything about that, but the only thing I can say is that there will be characters that have been involved in the Raccoon City incident involved in the game."

Ever since Requiem was first teased, fans of the series (me) have been spreading theories around theories (me, I did that) of Leon's return. I mean, come on, the setting is perfect, you can't return to Raccoon City and not find that floppy-haired dreamboat creeping around somewhere.
The theories got so huge that Capcom even had to go as far as to say that Leon Kennedy is absolutely not the protagonist of the next series, as he's just too cool to be scared by monsters any more. But they never conclusively said Leon wouldn't show up as a secondary character or as a cameo which, at the time, was all I needed to hear to keep the flame of hope alive.
Now we have producer Kumazawa on the record saying that not only will characters from previous games make an appearance in Requiem, but that it will be those who were "involved in the Raccoon City incident". Hell yeah.
You can probably tell that I'm pretty amped at this point. Sorry, Kumazawa-san, I have failed to heed your warning about not getting too excited about this news. But even with all my excitement about possibly seeing Leon in Requiem, I do also have to acknowledge all the other possible candidates.
For one, we've already seen Alyssa Ashcroft make an appearance in one of the trailers by her daughter's side. We could also see the likes of Ada Wong, Sherry Birkin, Jill Valentine, or one of the more likely candidates, Claire Redfield. There are plenty of classic Resi characters who could make an appearance in Requiem, but honestly, I'm only really interested in seeing Leon, although Ada would be nice too.