I don't expect anything super substantial for this E3, since apparently they still didn't decide on their plans regarding what it's going to be shown on this event. As I said in another thread, I fully expect hands on event to occur before E3 (in April or May), which would mean that Expo will be more likely an extension of that, allowing the attendees to play the same demo that journalists will play as part of the hands on event. Other then that, during the Microsoft conference they will probably show a new trailer for the game (either CGI Night To Remember style trailer or something akin to Launch Trailer showcasing the major features of the game), they will announce that The Witcher 3 and Cyberpunk 2077 will be backward compatible for the new consoles (possibly with announcement of free visual update for new consoles) combined with a reveal of a post release free DLC program and the story expansions for Cyberpunk that will come out in 2021.