Well Italian is the English adjective and Italiano is the Italian adjective for all things Italian so, essentially, the only difference is a difference of language. However, the adjective Italiano can change to Italiana, Italiani or Italiane according to the gender or plurality of the things its describes.

Italian (italiano [italjano] or lingua italiana [li
Kawa italjana]) is a Romance language of the Indo-European language family that evolved from the Vulgar Latin of the Roman Empire. Together with Sardinian, Italian is the least divergent language from Latin.