Kingsman 3 director Matthew Vaughn addresses why the trilogy-capper is taking such a long time. The Kingsman franchise was originally developed as a series of comic books set in the world created by Mark Millar. Millar and David Gibbons published the initial comics through Marvel in 2012, following the world of spies in the United Kingdom. The comics were then adapted for the first movie in 2014. Plans for sequels, spinoffs, and a television series have been in development over the years.
https://screenrant.com/kingsman-3-movie-delay-explained-matthew-vaughn/