Per the Disney Parks Blog:
At Disneyland Resort, the new Super Hero-themed land will begin recruiting guests in 2020, with even more new experiences to follow. The Guardians of the Galaxy will be joined by Spider-Man and the Avengers in what will become a completely immersive Super Hero universe, furthering the evolution of Disney California Adventure park. This new land will be anchored by the popular Guardians of the Galaxy – Mission: BREAKOUT!, in the adjacent space that is currently occupied by “a bug’s land.” “It’s Tough to Be a Bug” closed March 19 to make way for this new heroic experience; the rest of the land will close in late summer.
In addition to Disney California Adventure, new Marvel attractions will also appear in Disneyland Paris and Hong Kong Disneyland.