Square Enix has confirmed it is working on a Tomb Raider sequel for the next generation of consoles.
In an open letter, the company's Western CEO Phil Rogers confirmed that a sequel has been in development for some time.

I am also excited to reveal that we are well into development on a next-generation Tomb Raider sequel – something you may have heard about recently
A sequel was pretty much guaranteed considering the game's success. It's good to know for certain that the game is in development, that it's making good progress, and that it'll be on next-gen consoles everywhere.