Pinot Gris and Pinot Grigio are in fact the exact same grape variety. It is a white grape, with a grayish / brownish pink skin (hence the name gris, or gray, in French).
The grape originated in France (it's from the Burgundian Pinot family), and is known as Pinot Gris in France, where it is most cultivated in Alsace. Across the border in Italy it is known as Pinot Grigio. While French in origin, it is really the Italians that we have to thank for bringing such huge global recognition and fame to the variety.
While they are the same grape, the two names have come to infer two different styles of wine.
Personally, I find these qualities most prevalent in the Pinot Grigio wines from Alto Adige in Northern Italy, where the wines show great purity, and are delicately aromatic with great intensity and depth of flavor.
As for the Pinot Gris style, I am truly an ardent Alsace fan. Alsace Pinot Gris wines show incredible richness, breadth across the palate, earthy minerality and terroir.
Outside the motherland, I have also come to really love Oregon Pinot Gris, which in many ways combines the richness and texture of the Alsace style with the more vibrant fruitiness of the Italy style.
Sourced from: Thekitchn