Zero trust is the security model that stops trusting the network: every request is authenticated and authorised on its own merits, whether it comes from the office LAN or a coffee shop. Identity, device health and context replace the old castle-and-moat perimeter.
Hybrid work made zero trust mainstream, because the perimeter dissolved when the workforce did. For workplace software the implications are concrete: SSO with MFA on every login, least-privilege roles, and no special back doors for being in the building. The office becomes a place you work, not a place that grants access.