What cinematic universe includes the characters Optimus Prime and Megatron?

The Transformers cinematic universe, based on the Hasbro toy line, began in 2007 with the film directed by Michael Bay. Optimus Prime, leader of the Autobots, and Megatron, leader of the Decepticons, are the central characters of this saga that mixes live action with CGI visual effects. The franchise has expanded to more than six films, including the spin-off 'Bumblebee' (2018).