Can I use Managed AV (Microsoft Defender) alongside my current AV?

Team: Huntress EDR 
Product: Managed Anti-Virus
Environment: MAV Management
Summary:  Using Microsoft Defender with other AV 

In short, "you can, but you shouldn't." 

By default, in workstation versions of Windows (Pro, etc.), Microsoft Defender disables itself when a 3rd party AV is detected. 

Windows Servers do not automatically disable Defender when another real-time engine is present, but it's recommended that you disable Defender in scenarios to prevent conflicts. 

Please see Microsoft Defender Antivirus compatibility with other security products for more details.