Ms. Robredo, a 57-year-old former human rights lawyer and economist, is Mr Marcos Jr's main opponent in the May 9 election.
Her husband, a former cabinet member, died in a plane crash in 2012, prompting her to enter politics.
She ran for Congress for Camarines Sur in 2013 and was elected.
Ms. Robredo established a reputation as a politician who was hands-on with voters' issues, visiting low-income areas and remote provinces and speaking directly...