Though his participation in Black Panther's solo movie is yet to be revealed (it seems somewhat likely), we know for certain that Bucky Barnes will be taken off ice in Wakanda sometime this year. He's already been seen taking up arms against the invading throng of Thanos' army in Wakanda in the Avengers: Infinity War trailer and he should have a big part to play, given his invaluable military training.
And "arms" is the crucial word there, since the trailer reveals that the former Winter Soldier has had the augmented arm he saw destroyed in Captain America: Civil War by Tony Stark restored somehow. But it might not be the same. It might be better. Stronger. Faster. More bionic man-like. if anything.
That seems to be the suggestion coming from Infinity War co-director Anthony Russo, who spoke to Express UK to reveal just where the upgrade came from, and what it might mean:
“For everyone who’s seen Captain America: Civil War, they know Bucky was taken in by T’Challa in Wakanda. I think that, you know, we catch back up with him after he’s been there for a while. And if there’s an influence on his arm, it may perhaps have to do with that country that he’s been spending time in.”
So, that's basically an admission that he has a Vibranium arm, right? It couldn't be more heavily sign-posted - especially when you consider the Russos are generally quite overt about their marketing reveals. Perhaps this just isn't deemed all that important?
Then again, having a second weapon active in the MCU that uses Vibranium (and isn't wielded by a Wakandan) is still a big deal, and could well lead to some of Thanos' Black Order receiving a bigger punch than they might have been expecting.