Spider-Phoenix
#ChespinGang
I think you are refering to those hands-off they do in that CM after the current series' final episode and the preview of the new one.I honestly would not mind if we pulled a Super Sentai and introduced the next series’s traveling companion in the old series as some kind of preview.
Kamen Rider is the one who did the early bird cameo with the new lead rider showing up in the final episode in-story if I recall correctly. I think PreCure's done too but I've been out of loop in regards to it.