On 13 October 2015, Defensor Santiago controversially declared her second candidacy for President of the Philippines in the 2016 election after her doctors from the United States declared her cancer "stable" and "receded", but lost the election due to public concern for her health. In April 2016, her last appointed post was part of the International Development Law Organization Advisory Council (IDLO), an intergovernmental body that promotes the rule of law. She passed away from complications from her cancer on 29 September 2016, and was buried days later at Loyola Memorial Park in Marikina. In December 2018, the prestigious Quezon Service Cross was posthumously conferred upon Santiago, making her the first and, so far, only woman and the sixth person ever to be enthroned in the country's highest roster.