Several weeks ago, Microsoft’s head of gaming and former Xbox boss Phil Spencer seemingly confirmed that Gears of War 5 is on the way while discussing the plans for Xbox Game Pass, mentioning that "future unannounced games" for some "Xbox One exclusive franchises" such as GoW will be included in the subscription service. Now, it seems as if Microsoft is already moving ahead with development of the fifth numbered entry in the third-person shooter series, as several job listings on the developer Splash Damage's website suggest that to be the case.
Splash Damage is the company that worked on the multiplayer side of Gears 4, and the positions now open over on the developer's page include Associate Art Director, Cinematic Artist, Cinematic Environment Artist, Cinematic Lead, and more that look to be related to a potential Gears of War 5. While each of the listings state that they are connected to the franchise, one post that stands out in particular is for a Storyboard Artist, which infers that Splash Damage could be more involved with the game’s campaign than before, with the job post stating that the hire will be "inspiring the team and helping visualize the narrative while collaborating with the Cinematic Lead to ensure that the visual style and pacing is maintained."
All things considered, while Gears of War 5 is highly likely to come to fruition, there's always the possibility that the aforementioned job listings at Splash Damage are for another project relating to the franchise. Should Microsoft already be piecing together Gears 5, though, perhaps we will see it on display at E3 2018.
Source: Splash Damage