Snowpiercer was originally a set of three graphic novels done by Casterman in French and Titan in English.

1: The Escape
2: The Explorers
3: Terminus

Then they launched a prequel series which was also supposed to run 3 volumes:

1: Extinction
2: Apocalypse
3: Annihilation

That 3rd book was supposed to be out in 2021? I guess it was Covid-Delayed?