There are a few cases in which subject pronouns are required in Italian.

For contrast: Noi lavoriamo e tu ti diverti. (We work and you amuse yourself.)

For emphasis: Lo pago io. (I’ll pay for it.)

After the words almeno, anche, magari, neanche, nemmeno, neppure: Neanche noi andiamo al cinema. (We aren’t going to the cinema either.)

When the subject pronoun stands by itself: Chi voule giocare? Io! (Who wants to play? I do!)