FAQ

It's not necessary, but strongly advised. All three films tell a continuous story that take place over the course of a few weeks. Each film delves deeper in to the assassin mythos. Also, this film picks up immediately after the second film ends.

No. It's not outright stated, but there are organisations that have "A seat at the high table", it's implied that the Italians (formerly run by Santino D'antonio and his sister before him), Yakuza, Triads, Russians, and several others have representatives with seats at the high table.

There are then intricate lower-level factions that are associated with the high table but are not actually members, referred to as "under the table"; such as the Bowery King. Then there's your standard street level gangs that likely do business with the table or are recruited as foot soldiers for missions. So when a contract goes out on a high level bounty, i.e. John Wick, the message goes out to all the members of all the different factions and any associated street gangs.

John Wick: Chapter 2 (2017) ends with John being given 1 hour before being declared excommunicado. The last we see of him, he's running off with his dog. Chapter 3 starts immediately after.