Updated based on field comments

windows/security/threat-protection/microsoft-defender-atp/microsoft-threat-experts.md

@@ -26,6 +26,9 @@ Microsoft Threat Experts is a managed detection and response (MDR) service that
   
 This new capability provides expert-driven insights and data through targeted attack notification and access to experts on demand. 
 
+>[!NOTE]
+>Microsoft Defender ATP customers need to apply for the Microsoft Threat Experts managed threat hunting service to get proactive targeted attack notifications and to collaborate with experts on demand. A Microsoft Threat Experts subscription is a prerequisite for experts on demand collaboration. See [Configure Microsoft Threat Experts capabilities](https://docs.microsoft.com/windows/security/threat-protection/microsoft-defender-atp/configure-microsoft-threat-experts#before-you-begin) for details. 
+ 
 ## Targeted attack notification 
 Microsoft Threat Experts provides proactive hunting for the most important threats to your network, including human adversary intrusions, hands-on-keyboard attacks, or advanced attacks like cyberespionage. The managed hunting service includes:  
 - Threat monitoring and analysis, reducing dwell time and risk to the business