Star Wars the Clone Wars (the 3d series). The show started as a Jedi hack and slash with a few bits of Yoda life wisdom, droid misadventures and the odd galactic trade federation politics.

It matured into a series of jedi turning human soldiers against each other due to racism (speciesism?), A Jedi having to bury her entire battalion in a mass grave after Order 66 and one of the most poignant shots in all Star Wars history with Vader in the very last scene of the series.

From a literal sense, the show started in 2008 and with the final season dropping in 2020 after a 6 year hiatus due to the Disney acquisition,the characters in the show grew up and were given newer models to coincide with Anakin's appearance in Revenge of the Sith so the show also 'grew' up with its audience in a way.