One of the biggest questions coming out of Captain America: Civil War was, exactly what's going to happen to Captain America now that Steve Rogers has essentially turned his back on it? Will there be a new Captain America? If so, who will pick up the mantle? This is not what we expected the answer to be.
The above image comes from Sebastian Stan's Instagram account and apparently shows the Winter Soldier with his own Captain America style shield. It's mostly metallic in color, which is clearly designed to match Bucky's metal arm. He says it will come in handy, but for what?
To be clear, the creator of this shield, Casey McBroom isn't somebody who designs props for Marvel movies. Instead, he produces the shields for cosplayers and people who just want to own screen ready replicas of film props, so Sebastian Stan isn't walking around with an actual prop that we're going to see in Avengers: Infinity War. Having said that, this doesn't mean that there isn't a story reason that the shield wouldn't "come in handy."
Of course, the idea that the Winter Soldier is going to become the new Captain America seems completely bizarre as things currently stand. Right now Steve Rogers is in hiding to some degree after breaking half the Avengers out of prison. Bucky Barnes is in cold storage in Wakanda as scientists attempt to deprogram him. Even if the latter issue changed, The Winter Soldier is currently persona non grata among the Avengers thanks to that whole killing Tony's Dad thing.
Still, it's certainly possible that down the road things could end up exactly here. Bucky Barnes has certainly picked up the shield and fought as Captain America in the comics for various reasons. While this change taking place in the short term is unlikely, seeing this change happen down the road is much more possible. We have no idea what the future holds for most of the MCU once the Infinity War concludes. If Steve Rogers is not in a position to take up the shield at that point, it's entirely within the realm of possibility that Sebastian Stan could become the new Captain America.
Of course, there's also another strong contender for a new Cap if and when that moment happens. Sam Wilson, played by Anthony Mackie in the films, has also been Captain America in the comics. Both actors have been asked about possibly taking on the role in the MCU and both have done an admirable job of avoiding the question. It appears neither would have a problem taking a more prominent role in the franchise, though both have also stopped short of saying they want the job. Unless Sebastian Stan's new toy is his way of saying that now he's ready.