A suspension is temporary, the Home Office pauses your ability to issue new Certificates of Sponsorship while they investigate. You typically have 20 working days to respond. Depending on your representations, the licence may be reinstated, downgraded to a B-rating, or revoked.
A revocation is permanent. Your licence is cancelled, you can no longer sponsor any workers, and your existing sponsored employees' visas are curtailed to 60 days. There is no right of appeal, the only route to challenge it is judicial review in the Administrative Court.