The Winter Soldier is none other than Bucky Barnes. His transformation into this role was a result of manipulation and experimentation. Despite his past actions, he later strives for redemption and works to atone for his deeds.
The Winter Soldier made his debut in the comic world in 'Captain America #1'. It was a significant moment that introduced this complex character. Since then, he's become a staple in the Marvel universe.
The Winter Soldier doesn't become Captain America in the regular comic storylines. It's Steve Rogers who holds that position. But comics are full of surprises and alternate universes, so there could be special instances where this happens in some less common or alternate versions.