One previous showrunner is already returning to Doctor Who in the form of Russell T Davies, but fans think another might be joining him. Steven Moffat, who took over from Davies as Doctor Who's showrunner in 2010 and remained in the role until 2017, recently posted an image of himself outside a police box on Instagram. This quickly sparked rumors of Moffat's Doctor Who return. While Moffat's potential future with the sci-fi series is not yet clear, he could still be an excellent addition to the series' writing team under Davies.
Source:https://www.cbr.com/doctor-who-steven-moffat-return-conditions/