WGN America has renewed “Underground” for a second season, the network announced Monday. The series, created by Misha Green and Joe Pokaski, is currently averaging over 1 million viewers per episode in live-plus-same-day ratings and 3 million viewers in live-plus-seven. It was also the sixth highest-rated scripted series premiere of any cable drama this season. “With enormous pride we are announcing a second season of ‘Underground,’ a series that has resonated with so many passionate fans across the country,” said Matt Cherniss president and general manager of WGN America. “We are deeply proud of the work that the talented cast, crew and production team have done to bring this story…