Today during a Gears of War 4 livestream, Microsoft revealed that there is a Gears of War film adaptation in the works. Universal Pictures has optioned the rights for the property. According to the Hollywood Reporter, Scott Stuber (Central Intelligence, Free State of Jones, Ted) and Dylan Clark (Rise of the Planet of the Apes, Dawn of the Planet of the Apes, The Heat) will be producing the film through their joint production company Bluegrass Films.
No writer or director are onboard for the film yet. It's likely that it will start with Marcus Fenix' story, as opposed to the tale of his son that's taking place in Gears of War 4.
The first planned Gears of War film was announced way back in 2007, shortly after the release of the first game on Xbox 360. New Line Cinema purchased the rights to make the adaptation, with Collateral and 30 Days of Night screenwriter Stuart Beattie signing on to script the film. Underworld director Len Wiseman was attached to direct the film, which was planned as a prequel to the first game.
Then the project went absolutely nowhere.
By 2010, New Line Cinema had scaled back on the project considerably and Wiseman had moved on. Stuber entered the project in 2013 and his first look deal with Universal is what led to the film being put into production at the distributor.
Essentially, Gears of War has been in development hell for 9 years. There's no real indication as to whether the film will actually enter to production, or if their is just another step forward. Hopefully, it won't end like the Halo film did.