Crunchyroll released a brand new trailer for That Time I Got Reincarnated as a Slime Season 2 announcing its release on October 2020. The second season will be split into two-cours with the second half slated for release in April 2021.
Crunchyroll describes the show as:
Corporate worker Mikami Satoru is stabbed by a random killer, and is reborn to an alternate world. But he turns out to be reborn a slime! Thrown into this new world with the name Rimuru, he begins his quest to create a world that’s welcoming to all races.