If you're thinking to yourself that Transformers was on its fifth film - the last being The Last Knight - you're partially correct.
The upcoming spinoff movie, Bumblebee, with Hailee Steinfeld starring and LAIKA head-honcho Travis Knight directing, is considered to be the sixth Transformers movie. Anyway, Collider is reporting that the seventh Transformers movie has been pulled from its release schedule and effectively cancelled, which doesn't signal much in the way of good news for another Transformers movie.
Michael Bay has been repeatedly stated that he isn't interested in Transformers anymore - and just recently signed up with Netflix for a new project - so it may be that he's at long last done with the franchise he helped to build and define. Transformers has seen diminishing returns in recent years, going from over a billion in its early films - Dark Of The Moon made $1.124 billion, to be precise - to The Last Knight made just $605 million.
It could be that a new director may be the antidote to the sagging fortunes of the franchise, but one thing seems certain, it won't be Michael Bay's problem any longer.