One of the most crucial parts of the development of Star Wars: The Force Awakens was the decision to drop George Lucas' original story treatments; the series founder had already taken a step back with the sale of Lucasfilm, but this distanced him completely, a clear sign on Disney's part that the prequel age was now firmly in the past.
Given how that movie turned out, it was pretty much assumed the same would be true for Indiana Jones 5 (which is happening and will be released in 2019), but not so. According to Comic Book Resources, Spielberg has confirmed his return:
George is going to be an executive producer on it with me. Of course I would never make an Indiana Jones film without George Lucas. That would be insane.
So he's executive producer. That's a very vague title and can mean anything from giving it a thumbs up once its finished to acting as a producer in all-but-name, but the way Spielberg talks suggests some creative input. Hardly surprising given that the whole Indy thing is Lucas' baby (you could say he cared for it more than Star Wars), but after Kingdom Of The Crystal Skull, a movie he refused to approve until it had aliens as the MacGuffin, it seems like a poor move.
Indiana Jones 5 is set for release on 19th July 2019.