Coronal mass ejections (CMEs) are the most energetic phenomena related to magnetic activity and, by impacting the interplanetary space, they can be the source of severe planetary disturbances. Solar CMEs and their sources, such as flares and filament/prominence eruptions, have been intensively observed and studied over decades. The observations of stellar CMEs and their counterpart sources are still not possible in an easy and direct manner. As a consequence, the study of stellar CMEs sources did not receive the same attention as the solar ones. Nevertheless, with the advent of high-resolution photometric space missions, the observation of white-light flares has become more easily available. Still, it has not been possible to observe stellar CMEs directly. Instead, stellar CMEs are indirectly observed to be considered a natural effect of stellar flares or prominence eruptions. The increased interest in finding habitable planets in other planetary systems triggered a high interest in understanding the possible hazardous stellar events to their orbiting planets. Within this review of the Cool Stars 21 splinter session Solar and Stellar CMEs, we make a summary of the current status of the sources of the stellar CMEs, their observations and simulations.