It's highly unlikely we're ever seeing the sequel, but it was part of Rockstar's grand plan for a time.
Apart from Grand Theft Auto and Red Dead, Rockstar does have some other great IPs that fans often want to see return, Bully being one of them. Embodying the spirit of a young chap who just loves to make the lives of his fellow pupils and teachers hell, Bully was a great game.
And now, database miners have discovered mention of it in Rockstar's Grand Theft Auto V. It's very unlikely this means anything, as the game was in active development for two years before being stopped. This hasn't stopped people from having hope of a sequel though.
There's also mention of a Cops N' Crooks DLC for Grand Theft Auto V. Also, it's unlikely this will ever see the light of day, as the DLC was shut down following the passing of George Floyd back in 2020.