The official website of the anime Overlord, an adaptation of the light novel written by Kugane Maruyama and illustrated by So bin, has revealed that the fourth season of the series will premiere in July 2022. A new promotional video has also been released.
The cast of the previous season will return for this new animated adaptation.
Also, let's remember that the series will have a movie adapting the "Holy Kingdom arc".
The third season premiered on July 10, 2018 and could be watched on Crunchyroll.
Source: Overlord anime's website