Welcome To My Ted Talk

possible plot structure (potential spoilers)

Melina isn't in a white suit and her hair is braided as opposed to literally every shot we have of her in either of her suits has her wearing her hair in a ponytail. Also from the trailer see Melina more or less tries to discourage Natasha from going after the Red Room because she says something along the lines of "it's best to leave the past in the past" and "you're into going to get hurt". This is probably because Melina is running the new Red Room but at the very least Alexei and Natasha don't know that yet (I'm hesitant as to how much I think Yelena does or does not know).

So if Melina discourages them from going forward with the plan and they decide to go forward anyway; Melina calls Taskmaster on them.

Those shots from the trailer that are like pitch black and Taskmaster in some kind of quinjet type vehicle - based on similarly lit shots I believe he has Melina's house surrounded with the intent to capture Natasha (and probably Alexei and Yelena). We see Yelena inside the house with the lights all out and her gun seemingly clearing rooms but she's the only one we see - Melina, Natasha and Alexei have all gone AWOL. I suspect Natasha and Alexis manage to evade capture but Yelena gets taken and Melina was never in danger in the first place.
Which leads us to this confusing shot.

Half the time Yelena's hair is braided and the other half it's in a ponytail. In the shots from inside what I'm guessing is Melina's house, it's still braided (and she still has the vest on) but here the vest is gone and her hair is in a ponytail.