When does Counterpart return?

Counterpart is an American science fiction thriller television series starring J. K. Simmons. It was created by Justin Marks and was first broadcast on the premium cable network Starz. The series ran for 20 episodes across two seasons. It premiered on December 10, 2017, and aired its final episode on February 17, 2019.
Parallel Earths were created in 1987 during an experiment by East Germany when only a scientist named Yanek was on-site. The "Alpha world" Yanek met his "Prime world" counterpart, and they soon began studying how the initially identical Earths diverge. The differences between the two worlds become more pronounced after 1996, when a flu pandemic killed hundreds of millions in the Prime world.