Questions & Answers about O protetor solar está com você?
O is the masculine singular definite article, meaning the. Portuguese uses articles more often than English does, so o protetor solar simply means the sunscreen.
In this sentence, it sounds like the speaker is asking about a specific sunscreen that both people know about.
Literally, it is something like solar protector. In natural English, the usual translation is sunscreen.
In Brazil, protetor solar is a very common everyday term. You may also hear filtro solar.