This article explores the potential contribution of the Common Concern of Humankind (CCH) concept in the ongoing negotiations towards an International Legally Binding Instrument (ILBI) on the conservation and sustainable use of biodiversity in marine areas beyond national jurisdiction (BBNJ). Even though the CCH concept was discussed in the early stages of the negotiation process, it does not appear in the Zero Draft text. This article revisits the CCH concept and traces its historical evolution, including its incorporation in modern environmental treaty regimes. An analysis is undertaken of its scope and fundamental characteristics to ascertain whether the protection of BBNJ meets the CCH threshold. This article also reflects on the potential role of the CCH concept under the ILBI and whether it could bridge the gap between proponents of freedom of the seas and those defending the common heritage of mankind.