Superheroes and zombies have some kind of natural (or unnatural?) connection. Maybe it’s the clash of the icons; there’s nothing quite as memorable as a zombified Wolverine or a slavering Superman.
Marvel Comics was the first to realize this; as far back as 2004, Mark Millar, creator of the “Ultimates” alternative timeline of Marvel superheroes, bringing them into a far more realistic world (Hank Pym, spousal abuser?), brought in zombies, too. In the months and years to come, in various tie-ins and mini-series, the zombie virus that started infecting heroes as early as Ultimate Fantastic Four took over the whole world leaving a few hardy heroes to fight the apocalypse, and in later months and years, the virus would spread (as so often the case in Marvel and DC both) to other variations of the multiverse, so we could see even more devastation and transformation.
You could break your brain trying to cover all the crossovers and tie-ins, but if you want to see the best of the Marvel superheroes in zombie drag and some kick-ass, if often tragic, storytelling, your best bet is The Marvel Zombies Omnibus, which brings together the best stories into one wide-ranging tale of undead mayhem. (One lovely meta-irony: many of the key stories were authored or co-authored by Robert Kirkman, creator and king of The Walking Dead). It’s one huge paperback, but oh, the imagery! Oh, the joy and horror of a zombie Captain America!