My girlfriend is Sardinian and speaks Sardo. She's said to me in the past that it's fairly close to Latin, certainly closer than other languages (French/Spanish for example), but Sardo is generally a mix of Latin, Italian, with a few Spanish words.

Also worth noting there are different dialects of Sardo (such as Logudorese, in the north, if I remember the name correctly). And some dialects are closer to Latin than others.

In Italy/Sardinia dialects can be so far apart from one another that it's difficult to understand one another.