To prove to Steve that he had truly changed, Helmut Zemo used the power of the moonstones to restore the items he had destroyed when he and the Masters of Evil attacked Avengers Mansion. He also gave Cap a key that would allow him to escape from the prison that Reed Richards, Hank Pym, and the Radioactive Man were building.

This, of course, was just a ploy to get key players on his side so he would have every advantage available to him when he makes a run at immortality just to prove that he’s better than everyone else.

Helmut Zemo is a huge jerk.

   Thunderbolts #105