Originally Posted by spideymouse
I think they're going with platonic buddy cop mutual respect type thing. Almost like a bromance between a female and male. Even in the banter scene where she's trying to hook him up with Kristen from statistics, she's not so much romantically interested as trying to get Cap laid.
As for canon, I believe the only time they've hooked up is in the animated films Ultimate Avengers II and The Next Avengers: Heroes of Tomorrow. So no, not in the comics.
Just saw some spoilers (Pictures) in regards to Widow and Captain, although they might cut it from the final release.