Tokyo Ghoul Season 4 was pretty messed up, so fans were happy that anime ended. To make a decent adaptation of a 179-chapters manga in just 24 episodes is not a good plan when making any anime, so Tokyo Ghoul with its 24 episodes was doomed from the start.
Keneki’s story might be over, but fans are speculating about its return.
Tokyo Ghoul’s story has nowhere to re-start, so it is very likely that the return won’t be happening. The humans and Ghould live peacefully, and Kaneki has done what he planned to do, so it is pretty much a happy ending.
Ishida Sui might want to continue his manga, but at this moment he doesn’t, so we won’t be seeing Tokyo Ghoul Season 5.