Shingeki no Kyojin Wiki describes this:
Attack on Avengers is a one-shot manga crossover between characters from Attack on Titan and Marvel Comics properties. This is the first official Attack on Titan crossover, and the first official Marvel crossover with a manga/anime property. Hajime Isayama created the manga’s story, although Marvel’s C.B. Cebulski wrote the comic itself.
(May contain spoilers)