In the context of the film, Doctor Poison is a visually striking character who can be further explored if she were to appear in a sequel.
It can be assumed that Poison either escaped after that confrontation or was imprisoned by the Allied soldiers.
In a film with plenty of bright spots, one of the main criticisms levied against Wonder Woman was the lack of development for the villains in the film.
American audiences are most likely unaware of her talent, and therefore Wonder Woman will be their first exposure to her.