He appeared in Fantastic Four: Rise of the Silver, but instead of being the classic tall man in the outlandish purple costume, he was turned into a sentient cloud.
Few villains can pose a bigger threat to the universe than Thanos, but Galactus is one of those beings.
Galactus is in need of major cinematic redemption, but because he resides at Fox, the MCU can’t use him as its next overarching antagonist.