You must go to Naples and the Amalfi Coast. It usually comes very low in everyone's travel priority list but they are amazing places to go - trust me! Naples is the birth town of Pizza and Amalfi coast is the beautiful Italian coastline. Rest of the places like Rome, Pisa, Florence etc are also a good visit.
If you're into the outdoors, the Dolomites are a must. I spent five days there last summer and it completely changed how I see Italy. The hiking is amazing, but what stood out most was the cycling tours Dolomites region offers. Riding through those mountain passes was both challenging and unforgettable. I used cyclinghero.cc to find a route that matched my level (moderate, not hardcore). It was super helpful for understanding elevation, road conditions, and what towns to base myself in.