This perspective argues that the legitimacy of the UN Independent International Scientific Panel on Artificial Intelligence (IISPAI) depends as much on the demonstrable independence of its governance as on the quality of its scientific expertise. While the Preliminary Report offers an important contribution to global AI governance, it provides limited transparency regarding the management of funding, conflicts of interest, agenda-setting, and scientific disagreement. We contend that greater methodological and institutional transparency, alongside stronger structural safeguards for independence, is essential if the Panel is to serve as a trusted and authoritative source of scientific advice.