Three labels, one underlying question.
Search results and vendor pitches use "interim CIO," "fractional CIO," and "virtual CIO" almost interchangeably. In practice they describe different commitments, and the difference matters more than the title: is there a permanent seat sitting vacant right now, or a need that was never going to justify a full-time hire in the first place?
A second question sits underneath the first: does the organization need someone physically present on a schedule, or does it need reliable judgement on a recurring cadence, delivered however that gets done? Confusing those two questions is how organizations end up paying interim rates for a fractional-shaped need, or expecting fractional-level involvement from an interim placement.