This is usually a Pecorino Cheese, which has crushed black peppercorns stirred in.
The cheese mellows the flavour of the peppercorns, making them less overwhelming.
There is not one single producer or standard, because the name is not protected. Traditionally, though, it was made in Sicily.
It can be sold young, when it will be moist, or aged. It gets sharper as it ages.
When young, it can be used as a table cheese. When aged, use as a grating cheese.
There are other varieties of Italian cheeses that also come “pepato”, such as the American “Italian” cheese, BelGioioso, and specialty American versions of Romano.
“Pepato” means “peppered.”