Modern IT environments are more complex than traditional perimeter security was built to handle. Cloud and hybrid operations often reduce visibility and make it harder to enforce consistent policy across a mix of tools, teams, and procedures. Zero Trust assumes breach, which shifts the focus from prevention alone to strong post-breach controls that help limit impact when an incident gets through. Micro-segmentation is a key control that reduces lateral movement, contains threats closer to critical assets, and gives security teams more time to detect, respond, and recover.