No date announced yet. The new PV is here. This announcement comes after the final episode of season 3 aired earlier today. Check out the ANN article for additional information. Synopsis of the source novels from AniList:
Living alone and never having had a girlfriend, 37-year-old Satoru Mikami is dissatisfied with how his life has turned out. But after dying at the hands of a robber, he awakens to a fresh start in a new world…as a slime monster.
I liked season 3’s talking around a table more than season 2’s talking around a table, for the most part.
But if things finally shake out in the next season, that sounds like a lot of fun.