Every super PAC runs an independent expenditure campaign by definition, but not every independent expenditure campaign is conducted by a super PAC; the same kind of IE program could be run directly by a union, a 501(c)(4), or even an individual spender if thresholds are met for reporting.
The compliance and disclosure regime differs by entity type: super PACs have full political committee registration and FEC reporting, while non‑committee spenders making IEs file only IE reports once they cross dollar thresholds.