Mark Ryan, the voice actor for Jetfire and Lockdown in the "Transformers" films, has stated that "Transformers 5" will feature two storylines: one focusing on Earth and the humans; and the other set in space with Optimus Prime as the lead, as reported by Christian Post. Now, according to MoviePilot, there is still a chance the film will be primarily a prequel. 

Last year, in a report by IGN, producer Lorenzo di Bonaventura stated that they were still debating the issue of shooting scenes in space since those sequences would be devoid of human characters. However, Ryan's recent statement hints that the studios may be giving in to the notion of shooting a film set outside of Earth and without humans. 

Ryan explained that "Transformers 5" will still have Mark Wahlberg as the main human character but his storyline is set on Earth as he and the other Autobots fight a new threat attempting to take over the planet and wipe out humans. Optimus Prime's story, meanwhile, will involve the Quintessons and a possible encounter with the planet-eating Unicron. 

However, the report from MoviePilot suggests that the next film may be a prequel set entirely in Cybertron. The origins of the Autobots and Decepticons were hinted at in the first and fourth films, with a few lines of dialogue mentioning the Quintessons and a short flashback to the destruction of the planet and the All-Spark flinging toward Earth.

The actual war on Cybertron was never shown and neither have the films revealed who the Quintessons were and how or why they created the Transformers. 

MoviePilot also points out that there are rumors about another film, allegedly titled "Transformers One," which may be the prequel hinted at, while "Transformers 5" will be set in the modern day. Both films, however, are said to tie into each other as parts of one large cinematic universe. 

"Transformers 5" is currently slated for release in 2017.