Despite being polar opposites in terms of tone and genre, Hi-Fi Rush and The Evil Within share the same developer. Tango Gameworks was a studio known for its spookier titles, having developed The Evil Within 2 and Ghostwire: Tokyo, before shocking everyone with Chai and the gang. There are even a few nods to The Evil Within's protagonist Sebastian Castellanos throughout Hi-Fi Rush, as you can find him in robot form in multiple different levels.
However, it seems like robot Sebastian isn't the only nod to Tango's premium survival horror series, as this second discovery seems like pretty good news for everyone out there with their fingers still crossed for The Evil Within 3. First shared by GamesRadar, towards the end of Hi-Fi Rush you'll find yourself riding an elevator to the main bad guy's office for a climactic showdown. Once you reach the correct floor, a display is very briefly shown that tells Chai the floor number.
More importantly, at the bottom of the display is a very interesting piece of breaking news that states "sequel to popular survival horror game franchise anounced." It doesn't directly reference The Evil Within 3, but considering how long it's been since the second game, it would be a little odd to include if it was just a small nod to previous games in the series. Plus, the game already references The Evil Within so blatantly with robot Sebastian, so it's not like Tango Gameworks is just being coy.
It's certainly not impossible that The Evil Within 3 could currently be in development, especially considering that Ghostwire: Tokyo was originally going to be a third game in the series before it changed enough during development that it became its own thing. Just because Ghostwire: Tokyo released doesn't necessarily mean that The Evil Within 3 has been abandoned, and this little detail in Hi-Fi Rush could mean that we might be getting an announcement in the near future. Fingers crossed, anyway.