After the events of Captain America: Civil War, fans knew Sebastian Stan's Winter Solider would be showing up again sooner or later, but now fans have a more solidified timeline.
While there is a chance that the character might show up in Black Panther (they are keeping him in Wakanda after all), we now know he will definitely make an appearance in Avengers: Infinity War.
Stan has just been added to the upcoming We Have Always Lived In The Castle, which is being Directed by Stacie Passon and produced by Michael Douglas, Jared Goldman, Robert Mitas, and Robert Halmi Jr. Stan will play Charles Blackwood in the film, which starts shooting in Dublin this month, and in the same report (via THR), it is confirmed that Stan will start shooting Avengers: Infinity War early next year.
Exactly what his role will be in Infinity War is anyone's guess, as last time we left the character he was being put into cryostasis at Black Panther's compound in Wakanda, waiting for progress to be made on his Hydra programming. Thanks to Tony Stark he's also in need of a new arm, so suffice it to say he isn't in the best of shape.
Still, we don't know what happens in Black Panther, so his status at the beginning of Avengers: Infinity War is anyone's guess.