We all would have loved to have Poison Ivy in The Suicide Squad, the new version of this team of DC anti-heroes. But it will turn out that that will not be possible. James Gunn himself has confirmed that the comic book villain will not be included in the film, so we can forget to see who picks up Uma Thurman and Peyton List.
It has been through a question and answer session on Instagram that the information has come to light:

Well, nothing, without Poison Ivy. Regarding the film, we remind you that today James Gunn explained why he wanted to have John Cena for the role of Peacemaker; a couple of weeks ago, the former director of the Guardians of the Galaxy (before leaving with “the competition”) confirmed that The Suicide Squad was already “completely finished”, and praised Warner Bros. for not interfering in the production of the movie. Which by the way, we are still waiting for a trailer to arrive.
Source: Comicbook