A practitioner‑level whitepaper providing a clear, structured overview of SOC 2, CMMC 2.0, and NIST SP 800‑171/172, including their regulatory origins, control relationships, and applicability to organizations handling Controlled Unclassified Information (CUI). The paper explains how SOC 2 aligns with modern SaaS and cloud‑service security expectations, contrasts SOC 2 with the mandatory DoD CMMC framework, and summarizes the 110 controls of NIST 800‑171 and the enhanced protections of NIST 800‑172. A full SOC 2 readiness checklist is included to help organizations prepare for audit engagements and improve their security posture.