Politics, taxes and religion are always the top 3 in any culture. It Italy you might want to also avoid bringing up the Mafia, the Italian influence of World War II, criticizing Italian culture, negative Italian stereotypes, It’s also considered rude to inquire about the profession or income of someone you have just met. Family concerns are considered off limits along with off color jokes.
But the most important may be not to make negative comments about the local soccer team.