According to The Tracking Board, Goosebumps director Rob Letterman will be at the helm of the epic fantasy adventure. Although, to be fair, it's limiting to categorize D&D as "fantasy" but it literally crossed every genre and the movie could be just about anything. It could end up looking like Warcraft or Game of Thrones, or go in a sci-fi route. The site says the screenplay by David Leslie Johnson (Wrath of the Titans) will follow a warrior and a band of mystical creatures, including a half-dragon and cunning gnome, as they embark on an adventure to find a powerful treasure.
Hollywood has been angling to make another D&D film since the 2000 film bombed at the box office. In this case the producers, which includes original director Courtney Solomon, are looking for a Vin Diesel-type for the lead role. They probably have a good shot at scoring Diesel himself since he's an admitted D&D nut. The tone they're going for is also being described as in the vein of Guardians of the Galaxy, which Diesel would obviously know a little about.
So take all of this with a grain of salt until somebody confirms it. Knowing Warner Bros. they won't sit on this info for too long if it's true.