Confirmed by the GSC Game World website, the revival of the STALKER franchise comes after several failed attempts and the shut down of the GSC Game World back in 2011.
The new STALKER will actually be the fourth game in the series which started back in 2007 with STALKER: Shadow of Chernobyl and followed-up by STALKER: Clear Sky in 2008 and STALKER: Call of Pripyat in 2010.
GSC Game World was revived back in 2015 and launched Cossacks 3, an RTS game.
According to a Twitter post from Sergey Galyonkin, an employee of Epic Games, STALKER 2 has licensed Epic's Unreal Engine 4 for the next game and hopefully, we will hear more about it at the E3 2018 show or even sooner.
guess the engine, lol ????— Sergey Galyonkin (@galyonkin) May 15, 2018