Cantón is the Secretary of Human Rights in the Buenos Aires provincial government of María Eugenía Vidal. He will replaced David Michael Crane of the United States who "recently stepped down as a member of the three-person Commission", according to the OHCHR.
Cantón and co-commissioners Sara Hossain (Bangladesh) and Kaari Betty Murungi (Kenya) will "investigate all alleged violations and abuses of international humanitarian law and international human rights law in the Occupied Palestinian Territory, including East Jerusalem, particularly in the occupied Gaza Strip, in the context of the military assaults on the large-scale civilian protests that began on 30 March 2018".
Their aims will be to "establish the facts and circumstances, with assistance from relevant experts and special procedure mandate holders, of the alleged violations and abuses, including those that may amount to war crimes" and "to identify those responsible", according to the OHCHR.
Cantón has previously served as the director of RFK Partners for Human Rights at the Robert F. Kennedy Center for Justice and Human Rights; the Executive Secretary of the Inter-American Commission on Human Rights; and the first Special Rapporteur for Freedom of Expression in the Inter American System.