Looks like Naughty Dog is not finished with the Uncharted series. While Uncharted 4 gave closure to Nathan Drake's story, Lost Legacy's writer and director Shaun Escayg commented that the Uncharted series will continue.

Eurogamer recently asked Shayun whether Uncharted will end with the Lost Legacy, he responded:

"I wouldn't say it's the end. This thieving world is huge. There's so many characters. Even before we settled on this particular story we were exploring Sullivan, we were exploring Cutter, and pairing each other up, thinking what would be right, what would have conflict, growth, something new, something fresh. And Chloe was the one that kept jumping out. But to say the Uncharted world is done… I doubt that highly."

Uncharted: The Lost Legacy is scheduled to launch August 22 on PS4.