Seems that a chunk of the movie lays the groundwork for Black Panther movie.
1) the Hulk/Stark fight scene happens in a country that looks african (lots of black people on the street in clothes that don't look like american apparel, some shop brands from South Africa only)
2) Ulysses Klaw (Andy Serkis) is a Black Panther adversary, killed Black Panther's father in the comics, and is an expert on vibranium.
3) the lady undressing in the cave looks african, and vibranium is found underground, and may be Black Panther's sister, Shuri.
4) Wakanda is the only (fictionnal) country (in Africa) where vibranium deposits are found, and it seems obvious from the "molten metal Ultron fingers" and "broken Cap shield" of previous trailers that Ultron gets a body made out of vibranium at some point.
Also, it seems that the Hulk is under mind control during the street fight, becuase he has red eyes and so does Scarlet Witch when she is fighting the good guys, but what's odd is that the Mind Gem in Loki's scepter (that Von Strucker has since Cap 2) normally makes controlled people's eyes blue, not red... so that could be something else. Or they just went with red = evil but I doubt that.