https://www.gamespot.com/articles/no-multiplayer-in-ac-odyssey-but-the-franchise-isn/1100-6462180/

Ubisoft is once again exploring the possibility of adding multiplayer to Assassin's Creed. After 2010, several of the mainline Assassin's Creed games supported some form of a multiplayer mode, but the feature was cut after 2014's Assassin's Creed Unity.

In an interview with Game Informer, Ubisoft chief creative officer Serge Hascoet said, "We have many technologies, so it's case by case, but Assassin's Creed has no multiplayer mode, and that is very important for the social aspect of gaming, so we are looking for that."