Since the premiere, Ahsoka has blended old and new elements of Star Wars to tie together the various movies, television shows and other media at the franchise's core. At the beginning of Ahsoka, Episode 7, "Part Seven: Dreams and Madness," General Hera Syndulla stands trial for her actions throughout the series. While the trial seems grim, C-3PO, played again by Anthony Daniels, steps in with a message from Senator Leia Organa stating that she authorized Hera's mission, saving Hera from court-martial.
Source:https://www.cbr.com/ahsoka-c-3po-cameo-honor-original-trilogy/