The 3-Nen Z-Gumi Ginpachi-sensei spin-off novel of Gintama will appear as an anime. You can watch the trailer for it on the Gintama YouTube channel. Those who watched the show might already be familiar with the characters and AU that Ginpachi-sensei is, since there were occasionally segments of it after the credits. [Thanks, ryokutya2089!]
The trailer for Ginpachi-sensei brings Gintoki and Ginpachi together in a short skit sequence. Tomokazu Sugita, who voiced Gintoki in Gintama, reprised his role for both. In classic Gintama fashion, the trailer parodies both Spy x Family and Jujutsu Kaisen due to their popularity and success. At the end, Gintoki expresses shock and disbelief that Ginpachi is going to be the one who becomes the protagonist of the new anime and not himself.
You can watch the trailer for the Gintama spin-off Ginpachi-sensei here:
The original 3-Nen Z-Gumi Ginpachi-sensei debuted in 2006, and it ended in 2018. It features Ginpachi Sakata as a school teacher of the titular 3-Z class. Characters like the Yorozuya and Shinsengumi are members of the class, even though a good portion of them do not even look like high school students anymore.
3-Nen Z-Gumi Ginpachi-sensei is in development. More information on it will come out some time in the near future.
