Captain America vol 5 (start date 2004) issue #33 (published 2008)
Art by Steve Epting
Bucky Barnes, day 16
Bucky blamed Tony for Steve’s death, and targeted him for revenge. But Tony had a final letter from Steve asking him to do two things: keep Cap’s legacy alive, and help Bucky. Tony decided that meant convincing Bucky to step in as Captain America.
(You can see here that Bucky’s painted his arm in Cap colors as a memorial to Steve.)