"SCIF clearance" refers to having the necessary security clearance and "need-to-know" to be present in a SCIF without it being "sanitized" prior to entry and without escort.

SCIF is an acronym used by the US military to refer to a Sensitive Compartmented Information Facility. Typically access to such a facility requires a TS/SCI (top-secret special compartmented information) clearance specifically for the SCI (Sensitive Comparmented Information) being processed within the facility. SCI is not a "classification" so it is actually possible for information to be SCI but classified at the Secret or even Confidential level, although this is much less common than for Top-Secret information. SCI is based on the principle of "need-to-know" rather than the degree of damage that would occur if the information was disclosed (which is how Confidential, Secret, and Top-Secret classifications are assigned).