According to many of the people who have played The Last of Us it is not just the amazing single player experience that there is to enjoy, many of them say the online multiplayer mode is also worth playing and is quite enjoyable. Most of the developers who worked on the multiplayer in The Last of Us have reportedly returned to work on the multiplayer in Uncharted 4.
Naughty Dog Software Lead Game Designer Robert Cogburn shared the news in a tweet stating that "much of The Last of Us MP team have returned for U4 MP."
Cogburn also added that Robert Ryan and Quentin Cobb are "just a few" of the team members aiding in the work on the multiplayer in Uncharted 4.
At this time not much has been shared about how the multiplayer is going to operate in Uncharted 4, other then the evident fact that it exists, I imagine before years end we will have official word on how the multiplayer will work in the game.