We had no doubt that a The Last of Us 2 would be on its way, in fact for months now Naughty Dog and Nolan North have been teasing us with the existence of the game, while nothing before held any ground as they were likely simple confusions by the people mentioning the game, it now seems likely that we have solid proof.
During a recent stream for the upcoming Uncharted: The Nathan Drake Collection hosted by Naughty Dog's community strategist Eric Monacelli, writer Josh Scherr and lead animator Eric Baldwin they have essentially confirmed the existence of The Last of Us 2. During the presentation Scherr seemed to all but make an official confirmation.
"All the facial animation in the Uncharted series was led up by Eric, here,and [on] the first The Last of Us. Uh, did I say the first The Last of Us?”
If you watch the video above you can see how much Scherr stumbles over his words as he struggles with saying something he probably shouldn't have, he trips over himself constantly and repeats himself. It is likely that they could consider Left Behind as the second game, but I don't think this would cause so much of a stir, it is likely that Naughty Dog just let the news slip of their destined sequel.