The D23 Expo Japan 2018 returns to Tokyo Disney Resort starting February 10-12, 2018. Not many details are known at this time, but more information will be made available in Summer 2017 (also that’s when the tickets will go on sale). You can check the official website (Japanese only) and the D23 website.
This fan event is held at various locations and hotels at Tokyo Disney Resort (including the Tokyo Disneyland Hotel, Disney Ambassador Hotel, Tokyo DisneySea Hotel MiraCosta, and the Maihama Amphitheater).
The event was held back in November 2015 and was a huge success.
For more on Tokyo Disney Resort (also Hong Kong Disneyland and Shanghai Disneyland), make sure to visit TDRExplorer.com.