Grand Theft Auto V came out for the PC today. In tandem with that release, AMD has announced that GTA V is part of its Gaming Evolved initiative, and that the game supports its Contact Hardening Shadows (CHS) feature.
CHS uses factors such as the distance between a light source and an object, and the type of object casting a shadow, to render more realistic soft shadows. Radeon owners can enable this feature by selecting AMD CHS under GTA V's soft shadows graphics options.
Lest GeForce owners feel left out of the fancy soft-shadows club, Nvidia tells us that GTA V also supports its GameWorks Percentage-Closer Soft Shadows (PCSS) effects. This GeForce news post shows PCSS in action along with some other Nvidia-specific GTA V optimizations.
Update 4/18/2015: According to an email from AMD, GTA V is not part of the company's Gaming Evolved program. The game still supports the Contact Hardening Shadows feature.