Ant-Man and the Wasp's new TV spot is all about Ghost
https://www.cnet.com/news/ant-man-and-the-wasp-new-tv-spot-is-all-about-ghost/
"We've unleashed something powerful, we have to stop her," Hope van Dyne (Evangeline Lilly) says at the start of the trailer, which shows Ghost (Hannah John-Kamen) phasing through walls and fighting Scott Lang (Paul Rudd).
The previous trailer from earlier this month detailed that Ghost is from the Quantum Realm, and she's hoping to take over the world. The film takes place after the events of Captain America: Civil War, but seemingly before the events of Avengers: Infinity War (it's hard to imagine everyone being so upbeat if it took place after).