Pilot episodes are the make-or-break moment for many television shows. It sets the tone for the series and has the daunting task of introducing an entire show and its characters to an audience, all under a time limit of an hour (usually). Some shows are still finding their footing during the pilot episode and even so during their first seasons. Pilots have a huge amount of pressure applied to them, and the concept of pilots dominates the industry as everyone is trying to get their shows picked up.
Source：https://www.cbr.com/pilot-episode-definition/
