MCU: 12 Things We Learned From 4Chan's Latest Marvel Movies "Leak"
12. The Doctor Strange Sequel Plans
Doctor Strange will set up plot threads for future sequels: for instance, Mads Mikkelsen's Kaecilius turns out to be a vessel for icnic villain Dormammu and Chiwetel Ejiofor's character, Baron Mordo, betrays Strange in the end to set up his heel turn. He doesn't actually side with Dormammu though.
Most of that wouldn't be at all surprising. With Doctor Strange in this universe, Dormammu is likely to follow, even if it is a pretty big step forward into the cosmic realm for Marvel movies. But that's been foreshadowed heavily since the good Doctor was first teased.
And of course we already know Mordo turns out to be a villain: if he didn't it would be a massive betrayal of the comic book source. So it's no big shock to have that suggested at this stage: he and Strange have a long running rivalry (he's the ousted teacher's pet jealous of the new pretender, it's a tale as old as time) and it makes sense it will come to fruition in the movie.