The first season of Cosmos presented by Neil deGrasse Tyson (Cosmos: A Spacetime Odyssey, 2014) was a massive hit. On January 13, 2018, Fox announced another season titled Cosmos: Possible Worlds the trailer of which was released in July 2018. You can watch the trailer here:
The Season 2 was set to premiere in March, 2019 i.e. the next month. However, unfortunately, it seems that the Season 2 would miss its March premiere date.
This is because the host of the show and astrophysicist Neil deGrasse Tyson was accused of misconduct by several women in late 2018. Fox and the producers of the show launched an investigation into the claims soon after the news came out.

It seems that the investigation is still on and the makers of the show will take an appropriate decision soon after the investigation is concluded.
Cosmos: Possible Worlds will take us on a journey through the vast and unexplored realms of Earth and Space. For now, all we can say is that the show will not premiere on March 3.