Bucky Barnes' new Phase 5 role as the leader in Thunderbolts can help the Marvel Cinematic Universe complete his redemption arc. Although he joined the MCU as Captain America's best friend, his time as Hydra's super-soldier assassin The Winter Soldier forever changed his legacy. The countless people Bucky killed as Winter Soldier defined a huge part of his life and continued to haunt him in Phase 4, as evident in The Falcon and the Winter Soldier. Much of his actions in recent years have been tied to making amends for what he did in the past in an attempt to fully redeem himself publicly and in his own eyes.
https://screenrant.com/bucky-thunderbolts-lead-mcu-phase-5-redemption/