The official Twitter account for the That Time I Got Reincarnated as a Slime (Tensei Shitara Suraimu Datta Ken) TV anime announced that a second season is slated to air in 2020.
In addition, a new visual was revealed for the announcement.
Season one anime visual:
That Time I Got Reincarnated as a Slime (Tensei Shitara Suraimu Datta Ken) is a Japanese fantasy light novel series written by Fuse, and illustrated by Mitz Vah. It was serialized online between 2013 and 2016 on the user-generated novel publishing website Shōsetsuka ni Narō. It was acquired by Micro Magazine, who published the first light novel volume in 2014. Twelve volumes have been released as of July 2018. The light novel has been licensed in North America by Yen Press, who published the first volume in December 2017. It has received two manga adaptations and an anime television series adaptation by 8-Bit.
That Time I Got Reincarnated as a Slime synopsis:
Thirty-seven-year-old Satoru Mikami is a typical corporate worker, who is perfectly content with his monotonous lifestyle in Tokyo, other than failing to nail down a girlfriend even once throughout his life. In the midst of a casual encounter with his colleague, he falls victim to a random assailant on the streets and is stabbed. However, while succumbing to his injuries, a peculiar voice echoes in his mind, and recites a bunch of commands which the dying man cannot make sense of.
When Satoru regains consciousness, he discovers that he has reincarnated as a goop of slime in an unfamiliar realm. In doing so, he acquires newfound skills—notably, the power to devour anything and mimic its appearance and abilities. He then stumbles upon the sealed Catastrophe-level monster “Storm Dragon” Verudora who had been sealed away for the past 300 years for devastating a town to ashes. Sympathetic to his predicament, Satoru befriends him, promising to assist in destroying the seal. In return, Verudora bestows upon him the name Rimuru Tempest to grant him divine protection.
Now, liberated from the mundanities of his past life, Rimuru embarks on a fresh journey with a distinct goal in mind. As he grows accustomed to his new physique, his gooey antics ripple throughout the world, gradually altering his fate.
Source: That Time I Got Reincarnated as a Slime official Twitter