Alright y’all, head canon time.
What if, now here me out, Bucky has a secret child that not even he knows about.
We were shown on civil war (i think) that hydra was constantly trying to create more and more winter soldiers.
What if they decided to, instead of constantly brainwashing people, have two winter soldiers “mate” to create a new generation that could be raised in this life style and trained as a winter soldier.
What if they thought the best way to do that was by pairing up their two strongest. AKA Bucky Barnes (and whoever the strongest woman was).
So now, Bucky has a child (that they made sure he never new or forgot about, maybe told him that they decided to try a different way or it didn’t work or something like that), and that child is running around being the next great top secret assassin.
What if his child’s next mission is to kill Bucky to stop him from making amends.
What if they get to meet and Bucky finds out that hydra did more than he could remember. What if he tries to stop his child from going down that route and living a happy life instead.
Tl; Dr
Bucky might have a secret child that hydra kept from him.