Is the word team a pronoun?

No, the word 'team' is a noun (team, teams) and a verb (team, teams, teaming, teamed).

The noun 'team' is a word for a group of people joined in a common effort; a word for a group of animals harnessed together to pull something.

The verb 'team' is to join together for a task or goal; to put together in a coordinated ensemble.

Some dictionaries also designate the word 'team' as an adjective when used to describe a noun (team effort, team colors, etc.) However, this use can also be called an attributive noun, a noun used as an adjective to describe another noun.

A pronoun is a word that takes the place of a noun in a sentence.

The pronoun that takes the place of the noun 'team' is it.

Example: We have a great team this year. It has won the first three games of the season. (the pronoun 'it' takes the place of the noun 'team' in the second sentence)