When an assurance engagement concludes with no key controls being compromised but notes some opportunities for improvement, the most appropriate approach for the chief audit executive (CAE) is to send the final report to operational management. This ensures that the responsible management can act on the improvement opportunities. Additionally, notifying senior management and the audit committee that no significant findings were identified keeps them informed without overloading them with less critical details, maintaining transparency and proper communication channels. Reference: IIA Standard 2400 - Communicating Results, IIA Practice Guide - Communicating Assurance Engagement Results