Docker has revolutionized the IT world in recent years. Docker allows you to isolate processes so that they can be executed independently of each other. This allows us to make better utilize of the IT infrastructure because we can run several processes and apps separately. The isolation of processes increases security and reduces hardware dependencies (increases mobility).
Docker thus offers modularity, version control, easy rollbacks and fast hardware deployment. As time goes by, the work of infrastructure specialists is shifting to us developers. That's why we also speak of DevOps.
Docker is a containerization technology (see Kubernetes for orchestration).