Adobe Campaign is licensed on active profiles and message volume across email and other channels, with a committed annual baseline. Adobe sizes that baseline generously, because a large marketable base and a high send commitment are hard to reduce once they are written into the agreement.
The exposure is that both numbers drift. Profile counts inflate with stale and duplicate records, and send volume climbs with every new program. Cross the commitment and the overage rates apply, and few teams watch the marketable base closely enough to see the overrun forming.
Campaign is also bundled into Experience Cloud agreements where the line item cost is deliberately blurred. Isolating the Campaign line is the only way to know what it should cost you.