Atomic Blonde's lead actor/producer Charlize Theron has stated that work on a sequel is already underway. During a presentation last week at San Francisco's Castro Theater promoting her new film Tully, Theron spoke about her work on Atomic Blonde and preemptively announced the sequel news.
“We’re working on a sequel," she said (as quoted by IndieWire).
Atomic Blonde was a re-named adaptation of the Oni Press OGN The Coldest City by Anthony Johnston and Sam Hart. Johnston wrote a prequel with artist Steven Perkins which was released to coincide with the Atomic Blonde movie.
It is unknown if this film sequel will be an adaptation of that story, or an original story.