Bucky Barnes has been through the ringer in the Marvel Cinematic Universe, from nearly dying in World War II to being turned into HYDRA's brainwashed assassin to becoming a global fugitive. When we last left off with Bucky in Captain America: Civil War, he'd chosen to be put back on ice until the scientists in Wakanda could figure out how to erase the lingering Winter Soldier programming in his mind. This could have paved the way for Bucky to appear in Black Panther next year, but according to Sebastian Stan, we won't see him in T'Challa's standalone movie. Stan definitely stated:
I am not in Black Panther.
While a Black Panther appearance has now been ruled out, Sebastian Stan added to Good Morning America that Bucky's current status will be addressed in Avengers: Infinity War, so Marvel fans will still get to see him be thawed in 2018. This was confirmed in the special Infinity War footage screened this past weekend at D23, which showed Winter Soldier and Black Panther heading into battle with the Wakandan army. But as for Black Panther, Bucky will remain in stasis and oblivious to the challenges T'Challa has to face.
After spending decades as HYDRA's mysterious killer, only awakened whenever the terrorist organization needed him to eliminate one of their enemies, Bucky Barnes finally broke free from its control towards the end of Captain America: The Winter Soldier. Unfortunately, thanks to some pesky Russian trigger words that Helmut Zemo obtained in Captain America: Civil War, Bucky was sent into a murderous state, hence why he doesn't want to wake back up until all of HYDRA's programming has been erased. Since Bucky will be fighting in Avengers: Infinity War, presumably we can expect he'll be completely free of the brainwashing when he's reawakened. After all, if Thanos or one of his minions starts saying those trigger words, that's going to be a problem.
While Bucky Barnes rests in cold storage during Black Panther, T'Challa will have to deal with threats both within and outside of Wakanda. As if navigating his new royal duties wasn't enough, the movie's eponymous hero will also have to contend with Erik Killmonger and Ulysses Klaue trying to overthrow him. Fortunately, T'Challa will be aided by the Dora Milaje and CIA agent Everett Ross, but Bucky would certainly be another useful ally in this conflict. That said, it makes sense why Black Panther didn't throw another superhero into the mix given that this is T'Challa's time to shine. And besides, Winter Soldier and Black Panther be battling cosmic bad guys together just a few months later, as will almost every other major MCU hero.
Black Panther claws its way into theaters on February 16, 2018, and Avengers: Infinity War will follow on May 4.
