Microsoft Defender cannot be used together with other antivirus software such as Sophos Anti-Virus or McAfee Endpoint Security.
Defender for Endpoint includes capabilities that further extend the antivirus protection that is installed on your endpoint. You can benefit from running Microsoft Defender Antivirus alongside another antivirus solution.
For example, Endpoint detection and response (EDR) in block mode provides added protection from malicious artifacts even if Microsoft Defender Antivirus is not the primary antivirus product.
Microsoft Defender Antivirus compatibility with other security products https://learn.microsoft.com/en-us/microsoft-365/security/defender-endpoint/microsoft-defender-antivirus-compatibility?view=o365-worldwide
Hope this resolves your Query !!
--If the reply is helpful, please Upvote and Accept it as an answer–