When does The Unit return?

The Unit aired on CBS from March 7, 2006, to May 10, 2009 with the total of four seasons and 69 episodes. The series focuses on a top-secret military unit modeled after the real-life U.S. Army special operations unit commonly known as Delta Force. The Unit is based at a fictional army post, "Fort Griffith" The theme music for the first and second seasons was "Fired Up" by Robert Duncan.
The Unit was created for television and executive produced by David Mamet and Shawn Ryan. The show purports to describe the daily lives of Delta Force (called "The Unit" in the show) operators during training and operational missions. The Unit premiered on October 3, 2006, in the United Kingdom on Bravo.