I believe Guy has a valid point. There is the Jazz-World fusion style that basically is Jazz in its essence (swing/blues/whatever) that adds "world music" (I use the term for lack of a better one) ornamentation. That style of ornamented Jazz is quite common say, a specific North African/Maghreb/Andalus music.
The other Jazz-World fusion "style" (it's not a "style" per-se) is more of a true fusion in the way the 2 essences of the musical genres, say Jazz and Andalusian fused together into one. It is usually a fusion of distinct musical genres that the musician is fluent with. Jon Jang, Miguel Zenon, Omer Avital, Rabih Abu Khalil, Anouar Brahem, Abatte Berihun and Dudu Pukwana to name a few.