When does Z Nation return?

Z Nation is an American horror television series that aired on Syfy. The first season of 13 episodes premiered on September 12, 2014. The 68th and final episode aired on December 28, 2018, concluding the five-season series. Z Nation begins three years into a zombie apocalypse caused by a virus that has already killed most humans.
Alvin Bernard Murphy was one of three inmates at Portsmouth Naval Prison in Kittery, Maine, who were participants in a government-approved experiment. He is the only known survivor of a zombie bite who did not turn into a zombie. His blood contains antibodies that are humankind's last and best hope for a vaccine. He seems to be mutating into some form of hybrid between zombie and human.