When does Mercy Street return?

The series is based on the memoir, Adventures of an Army Nurse in Two Wars, by Mary Phinney von Olnhausen. It is set during the Civil War and follows two volunteer nurses from opposing sides. The first season of six episodes premiered on-demand on January 14, 2016 and made its broadcast debut on January 17, 2016 on PBS with 3.3 million viewers. PBS announced in early March 2016 that Mercy Street had been renewed for a second season which premiered on January 22, 2017. PBS cancelled the series after two seasons.