32 C.F.R. § 170.3
(a) The requirements of this part apply to:
(c) CMMC Program requirements apply to all DoD solicitations and contracts pursuant to which a defense contractor or subcontractor will process, store, or transmit FCI or CUI on unclassified contractor information systems, including those for the acquisition of commercial items (except those exclusively for COTS items) valued at greater than the micro-purchase threshold except under the following circumstances:
(e) DoD is utilizing a phased approach for the inclusion of CMMC Program requirements in solicitations and contracts. Implementation of CMMC Program requirements will occur over four (4) phases: