https://www.pcgamer.com/standalone-stalker-mega-mod-dead-air-is-here-to-help-tide-you-over-until-stalker-2/

Stalker 2 is in development, and at the moment, that's all I'm prepared to say with confidence. Developer GSC Game World quietly confirmed that the long-awaited sequel is indeed a thing earlier this year, but at the moment it's not expected until 2021. So in the meantime, why not have a go at Dead Air, a newly released mega-mod for the original Stalker. 

Dead Air comes to us from the folks who made Call of Misery, a notoriously difficult Stalker mod. But while Misery was a big influence on Dead Air, it does way more than ratchet up the difficulty. As the Dead Air team explains on Moddb, "it changes all aspects of the game, from graphics, audio, and special effects to various gameplay and AI features."