Different credential categories entirely
The CISSP is a vendor-neutral, senior, generalist credential. It does not test mastery of any specific tool, platform, or vendor. Its eight domains span the full security discipline conceptually.
The SC-200 is a vendor-specific, associate-level, role-based credential. It tests the candidate's ability to use Microsoft's security stack — Microsoft Defender for Endpoint, Microsoft Defender for Cloud, Microsoft 365 Defender, and Microsoft Sentinel — to detect, investigate, and respond to security incidents. Microsoft's role-based certifications, including the SC-200, are designed around specific job roles in Microsoft-heavy environments.