When does Tracey Takes On... return?

The show ran for four seasons on HBO and was commissioned following the success of the 1993 comedy special Tracey Ullman Takes on New York. Each episode focuses on a specific subject in which Ullmann and her cast of characters comment or experience through a series of sketches and monologues.
Tracey Ullman and her cast of characters "take on a different subject" for each episode of the series.