3) Scarlet Witch’s Powers
During Civil War, Scarlet Witch is basically grounded as the government thinks she is too powerful and volatile. They could be right if the character is anything like the comics version: Wanda’s powers have overwhelmed her and turned her evil numerous times, in the likes of such stories as House of M and Avengers Disassembled.
Another thing that fans will notice is that Wanda and Vision grow closer in the movie, which is presumably foreshadowing a future romantic relationship between the pair. This would follow the comics, where they got married and even had little witchy/android babies.
Vision also mentions how he doesn’t know what the stone in his head really is. Fans will know that this is the Mind Stone, one of the Infinity Stones, which the android will presumably find for himself in the upcoming Avengers: Infinity War.