Why does Cassius now yield to brutus' opinion?

Cassius yields to Brutus' opinion because he respects Brutus' reputation and integrity within Rome, believing that his moral standing will lend credibility to their cause. Additionally, Cassius recognizes that Brutus' involvement is crucial for uniting the conspirators and gaining public support against Julius Caesar. By deferring to Brutus, Cassius aims to strengthen their alliance and ensure the success of their plans.