We're less than a month away from the Nvidia DLSS and Nvidia RTXGI (ray traced global illumation), with a new 'Infinite Scrolling Volumes' feature which should greatly enhance the lighting of the game's open world.
While Icarus isn't the first game or open world title to ray traced global illumination, with Metro Exodus using the technology as early as 2019, RocketWerkz claims that the new Infinite Scrolling Volumes feature should make its implementation a cut above previous examples.
In a news post on the game's Steam page, Icarus developer Shammgod explains that the new feature "uses ray tracing to constantly update the Global Illumination lighting volume around the player as they move through Icarus' world. This effectively provides an "infinite" volume of global illumination for the player without needing a huge amount of memory to store an infinite number of lighting probes."
You'll of course need one of the Icarus system requirements demand a large amount of RAM.
Icarus is currently available on Steam with a 10% discount, but it's likely to go back to full price on release so you'd better grab it quick!