I have CADMUS being a spidery organization which has expanded out of a CIA off-the-books unit called Task Force X.  Waller is its head.

And the people she was on the phone to in my last Moon Knight post were "the Committee", a shadowy group of high minded white collar criminals (big business execs, scientists, etc) Waller has kept out of prison in return for providing a private company to find solutions and compartmentalize certain interests Waller and the government would prefer to maintain plausible deniability about.

So much as the Suicide Squad is a field team whom Waller trades freedom for favours to... the Committee does a similar thing for Waller in a more "hands off" way - although they pay their own independent field teams through contracts.