From the leaks, I’m pretty sure the four playable NATO classes are characters in the campaign. They were present in the reveal trailer, with a lot of focus on Isaac specifically.

Might be common knowledge, idk, but I theorize that Isaac will definitely be one of the main protagonists of the story, as he’s especially shown in a lot of cinematics. I know that the game will tackle multiple perspectives, and I think him and that one bearded soldier are top candidates in my eyes. We’ll see when the 26th comes around