Watch Train to Busan Presents: Peninsula (2020) online

Peninsula, the film directed by Sang-ho Yeon, is set on the Korean peninsula four years after the events narrated in the zombie movie "Train to Busan", directed by the director himself.
Jung-seok (Dong-Won Gang), is a former soldier who managed to flee the country during the zombie epidemic, to take refuge abroad. The man is now forced to return to Korea because he has been assigned a special mission with the aim of carrying out a recovery.
Once there, Jung-seok, to his great surprise, will realize that in the now isolated country from the rest of the world, there are human survivors.