Every TV show, movie, and book exists as reality in a parallel Universe whether by natural chance, creation by a God, or via the God like powers of the human collective consciousness. The sheer belief of the self-aware masses manifesting a new reality out of phase with our own. In the case of cartoons they may exist to an extent in other Universes similar to our own, or realities with varying laws of physics that allow for real cartoon existence. Places where everything literally looks like cartoon drawings,and life is just as wacky with a complete lack of logic! In some cases cartoon beings are unknowingly 2-D energy entities made of photonic light. Flat holograms existing in a world that appears 3-D to them. In some cases they may very well be 3-D holograms. It’s even plausible we are holograms ourselves within a simulation tricking us into thinking we’re biological beings.
Most of the time cartoon realities with sapient beings exist within advanced computer simulations. Top flight psychics, seers, and mystics have sensed such sentient cartoon simulations in our future, on alien worlds, and in high tech civilizations within parallel Universes. They’ve also vaguely sensed actually Universes where cartoons are real. So yes indeed cartoon characters, such as Homer Simpson, are in fact real animated people somewhere in our vast infinite Macroverse where everything is possible! In fact we ourselves exist as cartoons in those worlds since it’s just another mathematical probability to play out in the hands of the Gods.
There are also Bitmoji worlds where the skies are always sunny, and rainbow ridden. Realities where we exist as generally happy people who speak in goofy short slang phrases. Only clouds, and rain bring angst amid the Emoji animals who frolic about with glee!