Captain America by J.M. DeMatteis

Another underrated run. Preceding the epic 100+ issue run by Mark Gruenwald, DeMatteis' run tends to get overlooked by a lot of people. Despite that, it has some pretty important stuff going on: mostly the death of the Red Skull and the first proper appearances of Baron Helmut Zemo, 50s Bucky as Nomad and Sin as well as future Spider-Man villain Vermin.