Last year Ant-Man and The Wasp hit theaters and ended up making about $100 million more than the original, and when a sequel does that; they usually want to make another.
According to Entertainment Tonight, Michael Douglas has heard some talk about a third Ant-Man:
“There’s been talk [about another Ant-Man]… [but] there’s been nothing formal right now that I know of. They always kind of spring it on me. The first time you hear about it, it’s already in its third rewrite.”
If you remember, Ant-Man and The Wasp was a mid-Phase 3 announced movie; it wasn’t part of that big Phase 3 reveal. If they’re already talking about a third movie, it’s very possible we won’t have to wait long into “Phase 4” to hear about it.
Personally, I think a third Ant-Man would be a perfect place to introduce the Fantastic Four to the MCU. The Ant-Man movies share similar themes and tone to what the F4 should be, and Peyton Reed was involved with Fox’s early ideas of the franchise in the early 2000’s so it’d be a perfect it.