Secure Access Service Edge is essentially the convergence of several existing cloud-based security technologies. CASB offers a security gateway between IT infrastructure and that of a cloud provider. CASBs provide IT managers with visibility into cloud services in use across the enterprise and enable the managers to implement security controls. CASBs enable shades of access, which is more useful than a binary decision to block or allow. CASB is a critical tool organizations can use to holistically secure an organization from endpoint to cloud. It provides the same visibility and control provided by a “castle and moat” security approach.”]
Source: https://www.cuinfosecurity.com/blogs/what-casb-do-you-need-it-p-3119