Kingdom Hearts 3 is not the end of the series. There are more games planned that will be teased in the secret movie and epilogue.
Tetsuya Nomura gave an interview to Famitsu in which he answers some questions for the game. The interview is available to read online in Japanese but here is a rough translation of what he has said in the interview.
If you don’t know, Square Enix is also planning to release the epilogue and secret movie with an update after the game releases tomorrow. The epilogue will be out on January 26th while the Secret Movie is set to drop on January 31st.
Kingdom Hearts 3 will be out in Japan on January 25th while the rest of the world release is planned for January 29th. The review embargo is expected to drop today so you can get early impressions from the critics if you want to know the quality of the game.
Source (Famitsu)