Naughty Dog really are the crown jewel in Sony's gaming repertoire. The developer works exclusively for the company and it's likely the biggest first party developer between the Xbox and PlayStation. They're currently working on the fourth game in the Uncharted series and the recent footage suggests that it's coming on to be something quite special.
Uncharted isn't the only critically acclaimed franchise the developer holds mind. The Last of Us was the darling of 2013 and it appears the future might hold more for the series. CVG have pointed out that the Linkedin profile of Michael Knowland, an ex-Lead Character Artists, says that he worked on The Last of Us 2 for a month.
CVG report that the title was previously listed as 'Untitled AAA Game' before changing to 'The Last of Us 2'.
This of course doesn't guarantee a game in the future. Many games go through concept stages before they are scrapped. Also, The Last of Us wrapped up in a way that doesn't leave a ton of room for direct sequels.
That said, I wouldn't bet against a "and one more thing" moment from Sony's E3 Press Conference next year where they announced the game. That would be quite something.