Producer Lorenzo Di Bonaventura says a followup to Transformers: The Last Knight is being developed, along with the Bumblebee sequel. You may recall that Paramount had originally intended for The Last Knight - the fifth live-action Transformers movie overall - to kick off a shared universe of prequels and sequels featuring the robots in disguise. However, that was before the Michael Bay-helmed tentpole bombed with critics and disappointed at the box office in 2017, leaving the future of the franchise in doubt. It also put more pressure on last year's '80s-set prequel Bumblebee to reverse the series' downward trend and earn the property some much-need goodwill.
Fortunately, Bee's solo movie was up to the task. Although Bumblebee made less at the box office than Bay's five Transformers films before it, the Travis Knight-helmed adventure was a hit with critics and ultimately made its way to profitability, buoyed by the good word of mouth. It was thereafter reported that Bumblebee would serve as a reboot for the Transformers movies at large - an idea that seems to somewhat conflict with today's news.
Speaking to Cinema, Bonaventura (who has produced all the Transformers movies to date) confirmed that a sequel to Bumblebee is in the works, as previously reported. However, he then revealed that a film set in "the main family series following the events of Transformers: The Last Knight" is also in active development right now.
To be fair, there's room for interpretation in Bonaventura's comment. The Last Knight "sequel" that's being developed might be more of a soft reboot than a strict continuation of the fifth Transformers movie. That wouldn't be anything new for the franchise either; after all, 2014's Transformers; Age of Extinction was also a partial relaunch that focused on a different group of humans than Bay's original Transformers trilogy. That said, The Last Knight included some major plot threads that were left dangling for the sequel to pick up - namely, that earth contains Unicron, Cybertron's ancient enemy. It's possible, then, that the followup that Bonaventura mentioned will aim to build on that foundation and, at the same time, introduce yet another group of human heroes to share the screen with Optimus Prime and his fellow Cybertronians.
At this point, though, the larger Transformers continuity is so confusing that fans might prefer it if Paramount simply focused its efforts on the Bumblebee sequel and gave up on trying to continue The Last Knight's narrative in any way at all. They might end up doing just that, if they decide that reviving their initial plans for a shared universe is more trouble than it's worth. On the other hand, there are no doubt those who want to see the payoff to Transformers: The Last Knight's Unicron tease, especially since Bay is no longer working on the franchise. For now, we'll just have to wait and see what happens.