Fallout: New Vegas is a very well-regarded action RPG and is arguably the best of the 3D Bethesda-published Fallout titles yet released. Unfortunately, due to its age it’s a bit clunky from a “modern” gameplay perspective, and because of its incredibly short development cycle lending to sub-optimal performance, it can be a bit of a chore to run stably on a “modern” computer. However, a team of dedicated modders are currently working on a mod which consists of New Vegas, built completely from the ground up to run on Fallout 4. This mod will include completely redone voice work (for legal reasons) and even features the legacy SPECIAL and Skill systems from the older Fallout titles, instead of the leveling system seen in Fallout 4.
There’s currently no word on a release date, but it’s sure to be worth the wait.