Complex sentence: The Pinkertons have been featured in season 3 of the HBO series Deadwood, as well as in season 4, episode 11, of the HBO series Boardwalk Empire, the character Roy Philips is revealed to be a detective working for the agency.
Split into simpler sentences: The Pinkertons have been mentioned in season 1 and featured in season 3 of the HBO series "Deadwood". Besides that, in season 4, episode 11, of the HBO series "Boardwalk Empire", the character Roy Philips is revealed to be a detective working for the agency.