CMS stands for the Centers for Medicare and Medicaid Services. CMS is part of the U.S. Department of Health and Human Services and is an authority having jurisdiction (AHJ) over healthcare facilities.
CMS performs hospital surveys, or contracts with third-party accrediting organizations (AOs), like The Joint Commission (TJC), to do them on their behalf. Hospitals are able to choose which AO they wish to work with.
Hospitals that participate in the Medicare and Medicaid program must maintain compliance with CMS and the standards set forth by its AOs in order to be considered for reimbursement.