Primitivo and Zinfandel are closely related, often considered to be the same grape variety, but they show some differences due to their growing conditions and winemaking practices. Both grapesl trace their origins back to Croatia, where they are known as Tribidrag or Crljenak Kaštelanski. DNA profiling has confirmed that these two names refer to the same grape variety, though they have diverged into different clones over time due to their cultivation in distinct regions—Primitivo in Italy and Zinfandel in the United States

So, when you see both varietals on a wine menu, from the same country and/orproducer - you may well get similar product but they will be different depending on the micro locations grownand the winemaking technique

Zin Typically offers bold, spicy flavors with notes of black pepper, ripe berries, and a deeper ruby color. ...

Known for its intense fruit flavors, including black cherry and plum, Primitivo wines tend to be lighter in color with a more purplish hue. 

Most Zinfandel grapes thrive in California's sunny conditions, leading to a jammy fruitiness . In contrast, Primitivo grapes are are grown under the Southern Italian sun under the hot Italian sun, resulting in a wine that is typically less fruity and less sweet