With the free Party Mode update that arrived on July 4, 2017, up to four players can team up online to tackle Cooperative Operations, i.e., Bounties, Invasions, Loot Trucks, Races, Showd0wn, Man VS Machine Robot Fights, and the DedSec Virus events, or explore the city of San Francisco in Free Roam and gather collectibles.
Following Chicago, San Francisco becomes the next city to install the ctOS surveillance system, (the Central Operating System), which connects everyone with everything. The game features a new protagonist named Marcus Holloway, who is a young, intelligent hacker from Oakland. He was wrongly framed for a crime he did not commit when he was still a child by the upgraded ctOS system, ctOS 2.0, which connects his personal information to the crime. Realizing the system brings harm to the innocent citizens of San Francisco, he decides to work with the hacking group DedSec to take down the city's ctOS 2.0, and Blume, the creator of the ctOS system