The official TOHO animation YouTube channel released the first trailer for the upcoming fourth season to Haruichi Furudate’s hit manga series Haikyu!! titled Haikuu!!: To the Top. The series is scheduled to premiere on January 11, 2020 in Japan. Online streaming simulcast details have yet to be announced.
Crunchyroll describes the show as:
Based off of the original Weekly Shonen Jump manga series from Haruichi Furudate, Haikyu!! is a slice-of-life sports anime revolving around Shoyo. Inspired by a small-statured pro volleyball player, Hinata creates a volleyball team in his last year of middle school.
The first three seasons are currently streaming on Crunchyroll and HiDive.