The team leader who is leading them is my brother.
Explanation:
An adjective clause is a group of words that includes a verb and a subject. Moreover, it modifies a noun or a pronoun, just like an adjective does.
One sentence of an adjective clause beginning with the relative pronoun "who" is-
<u><em>The team leader who is leading them is my brother.</em></u>
In the above-given sentence, "the team leader" is the subject while "who is leading them" is the adjective clause. And this adjective clause modifies the noun "team leader".
