It depends. Some serials are inspired by real events and people, but they might take creative liberties and fictionalize parts for entertainment purposes.
Not all serials are based on real stories. Many are purely fictional creations made up by the writers' imaginations. However, some do draw elements from real-life incidents and mold them into a coherent narrative.
It varies. Some serials aim to accurately depict real stories, while others use real events as a loose framework and build a mostly fictional story around it. The degree of connection to reality can range widely.