Thanks to GameStop's product page for Watch Dogs, we now have a better idea as to what is entailed with the game's Season Pass. For $19.99 — a 25 percent savings compared to buying the DLC individually — you'll get "a unique single-player campaign featuring a new playable character plus more missions, weapons, and exclusive content."
Ubisoft has yet to formally announce the Season Pass, but it sounds plausible. Of course, forking over an additional $20 without knowing details sounds a bit crazy to me, so I'd suggest waiting until they share some more information.
Meanwhile, the PlayStation versions of the game will receive four exclusive missions totaling 60 minute added gameplay along with a new outfit for game protagonist Aiden Pearce. The official description reads: "In an original mission exclusive to PlayStation 3 and PlayStation 4, Dedsec requires the help of Aiden to set the record straight and expose a company’s deceitful activities," Schmidt detailed. "More precisely, they need Aiden’s help, his connections, and his extreme knowledge of Chicago’s complex ctOS network to track down enemies and expose them for who they really are, and he’s willing to do it – for a price."