Wakandan kids call Bucky "white wolf" in a post-credit scene.
In the comics, White Wolf is the name given to T'Challa's adopted brother, who real name is Hunter. Hunter ended up in Wakanda after a plane he and his family were on crashed-landed in the country. His parents were killed, so T'Chaka adopted him. He later became the leader of Wakanda's secret police force.
Though the name is unrelated to Bucky in the comics, it seems like the Marvel Cinematic Universe is changing the role to fit the Winter Soldier.
Read our full post-credit breakdown here