Director Michael Bay's 2014 film Transformers: Age of Extinction further showed that for now the Transformers movie franchise is critic-proof, as it grossed over $1 billion worldwide even in the face of mostly negative reviews. Nonetheless, there has been some question as to what will come next for the franchise; for months now, Paramount Pictures has had a team of writers collaborating together (as a "Writing Group"), to brainstorm ideas for how to expand the property into a Shared Transformers Cinematic Universe encompassing multiple future sequels and spinoffs.
The latest update on the subject indicates that Transformers 5 - e.g. a direct continuation of events in Age of Extinction - remains the next Transformers project expected to go into production. However, it seems that an animated film/spinoff (an origins story, at that) is now slated to follow thereafter.
Deadline is reporting that the Transformers Writing Group "experiment" is done, with Oscar-winning screenwriter Akiva Goldsman - who has already dipped his toe in genres ranging from post-apocalytpic (I Am Legend, Insurgent) to futuristic sci-fi (Lost In Space, I, Robot) to superheroes (Batman Forever, Batman & Robin), with varying results - up to pen the script. The Deadline report also states that Mark Wahlberg is set to reprise his Age of Extinction role as inventor Cade Yeager with Bay directing, but Bay has already taken to Twitter claiming a deal has not yet been finalized:
Re: directing TF5. No, it's not official. I have not committed to any idea as of yet. Just met with Steven and we are discussing.
— Michael Bay (@michaelbay) September 17, 2015
Bay isn't exactly known for being forthright when he addresses rumors and/or reports about his work, but it is possible he's not formally committed to directing Transformers 5 yet and is simply discussing ideas with the Transformers series' executive producer Steven (Spielberg) right now. Deadline's report asserts that production on the fifth Transformers live-action movie will start in June 2016, so it's also possible that Bay just hasn't nailed down a deal to call the shots this far ahead of time. Odds are that he does direct the film, though (... for better or worse).
The other key piece of information featured in Deadline's article is that the project currently planned to follow after Transformers 5 is an animated spinoff - one which would serve as an origins story for the Transformers' home world of Cybertron, as it were. That project, which is now being written by Andrew Barrer and Gabriel Ferrari (who handled rewrites on Marvel Studios' Ant-Man), is presumably the same Cybertron prequel movie that's been rumored for some time now. That said, Deadline doesn't specify if the spinoff will directly tie into the live-action Transformers films mythology or be more standalone in nature (see the non-Marvel Cinematic Universe based 2018 Spider-Man animated film).
Nonetheless, it seems fair to assume the animated Cybertron film will, in fact, take place in the same "Cinematic Universe" as Bay's movies - seeing as that was (seemingly) one of the main goals behind the assembling of the Writing Group in the first place (read: build the Transformers Shared Universe). It shouldn't be too difficult to integrate such an "origin story" in the franchise, seeing as that Bay's Transformers films haven't touched on the early history of the Autobots and Decepticons' home world - and such a spinoff would have to place the focus more on alien robots, rather than humans (as many Transformers fans have long wanted to see happen).
It's all worth noting that news of a big screen Cybertron prequel gels with the recent rumors that the Transformers movie franchise will be "going cosmic" in the future - and again, that's an idea that many fans should be able to get behind.
Transformers 5 is tentatively expected to reach theaters in 2017; we'll let you know when the film gets an official release date.