A Neo-Western film carries over the themes and traditions of the typical Western genre, but one with one variation: a Neo-Western takes place in the contemporary world.
Some examples of Neo-Westerns include No Country for Old Men (2007), Hell or High Water (2016), and even Logan (2017). While the settings of these films do vary (one takes place in the 1980s, another 2016, and another 2029), they all implement similar themes of isolation, the “open road,” and traditional Western imagery, like this:

The above image is from West Texas; as it just so happens, all three films listed above primarily take place in West Texas. However, that doesn’t mean that a Neo-Western must take place there, or even in the desert; as long as it maintains the tone of a Western, a film can still be a Neo-Western (take Wind River, for example).
In order to see a Neo-Western in action, I’ve embedded a scene from each aforementioned example below: