In the following episode "The Woman Who Lived", the Doctor catches up with Ashildr in 1651 England after 800 years have passed for her.
When the Doctor next encounters Ashildr in "Face the Raven", she runs an alien refugee camp hidden in the heart of 21st century London, having lured the Doctor in using Rigsy (Joivan Wade), an old acquaintance of his, as bait.