Learn Italian: Noi siamo in città, ma non ci sono negozi aperti. - We are in the city, but there are no open shops.

Ci sono means "there are" and is used because negozi (shops) is plural. If we were talking about just one shop, we would use c'è (there is).

How do you say "there are no" or "there aren't any"?

You just put non right before ci sono. So, non ci sono simply means "there are not" or "there are no". You don't need an extra word for "any".

Why do both negozi and aperti end in -i?

In Italian, adjectives must match the noun they describe. Negozio (shop) is masculine, so its plural is negozi. The adjective aperto (open) changes to its masculine plural form aperti to match. Also, notice that the descriptive adjective comes after the noun: negozi aperti (open shops).

Why is it in città instead of nella città (in the city)?

When talking about being in a city or going to town, Italian often uses just the basic preposition in without adding the word for "the". It acts like a set phrase, similar to how in English we say "in town" instead of "in the town".