Pinot grigio and pinot gris are actually the same white wine grape, just with two different names. Just as with pinot blanc, pinot gris (the actual “technical” name) is thought to be a mutation of the pinot noir grape.
The confusion over the name is a result of where the grapes are grown. For example, in Italy and California, wines produced from grapes called pinot grigio, however, in France, Canada and Oregon it’s referred to as pinot gris. The main difference is in the style is a result of the climates the grapes are grown in and how the wines are produced. In Italy, pinot grigio tends to be dry, with a citrus-centric core and a minerally finish. In France, the wines lean more towards stone fruits and white flowers. Both styles are found throughout the grape-growing world, so it’s just a matter of finding the variety that appeals to your palate.