The Avengers 4 Will Have Wasp
"An initial script has been created [for Ant-Man and the Wasp]. It has not been approved by the higher powers that be. The 'Feige's,' Lilly told Blastr. "I haven't seen the script, yet. I have talked to [director Peyton Reed] about where they are heading and what they want to focus on. I'm excited because it's essentially going to be the origin of the Wasp. Of course we are going to see Wasp for the first time and take on the mantle and put on the suit and fly about and do her thing."
Lilly also offers Wasp won't be featured in Avengers: Infinity War.
Following [Ant-Man and the Wasp], there's an Avengers series coming out, that's a two-parter, and the Wasp won't be in the first part [Avengers: Infinity War], she'll be in the second part [Avengers 4] because they really want to preserve that reveal for Ant-Man and the Wasp. So they can give it it's due time..." Lilly said.
Ant-Man and the Wasp has a July 6, 2018 release also starring Paul Rudd; The Avengers 4 hits May 3, 2019. The Avengers: Infinity War has a May 4, 2018 release.