Conditional access
Policies that decide whether to allow, block, or add requirements to a sign-in based on the context of the request.
Signals include the user, the application, the device, the location, and the calculated risk of the sign-in. A policy can require a compliant device for access to finance systems, block sign-ins from countries you never operate in, or force reauthentication when risk is elevated.
It is the practical implementation of zero trust in a Microsoft environment, and the most consequential set of policies in the tenant. It also carries real lockout risk, which is why break-glass accounts are excluded from every policy.
Where this comes up
Conditional access sits inside our identity and access work. If you are trying to work out what this means for your own environment rather than in the abstract, that is the page worth reading next, and a short call will get you a straight answer faster than either.