• Philippine voters will head to the polls in May 2022 to elect a successor to President Rodrigo Duterte, whose six-year term in the country's top office is coming to an end.
• Duterte has set his eyes on a different political office, filing his candidacy for a senate seat in next year's general elections.   
• Dozens registered to run for the Philippine presidency, including the current vice president, the son of a former dictator and a retired boxing champion.
• Here are four presidential candidates to watch.

Philippine voters will head to the polls in May 2022 to elect a successor to President Rodrigo Duterte, whose six-year term in the country's top office is coming to an end.

Duterte, who sought closer ties with China for most of his term, is prohibited by the Philippine constitution from seeking a second term. The president has set his eyes on a different political office, filing his candidacy for a senate seat in next year's general elections.   

Still, much of the attention on the Philippine elections would fall on the presidential race, which analysts said remains wide open. Campaigning for national positions — which include the presidency and senate — will start in February.

Dozens registered to run for the Philippine presidency, including the current vice president, the son of a former dictator and a retired boxing champion.

Notably absent is Duterte's daughter, Sara Duterte-Carpio, who led opinion polls as the preferred presidential candidate. She instead registered for the vice-presidential race, to the surprise of many observers.

While Duterte had endorsed current senator and loyalist Christopher "Bong" Go, his daughter had backed a different candidate. On Tuesday, Go announced he was withdrawing from the presidential race. He initially filed to run for vice president before withdrawing to run for the top job.

Here are the presidential candidates to watch:

Ferdinand 'Bongbong' Marcos Jr.

Ferdinand "Bongbong" Marcos Jr. is the son and namesake of late dictator Ferdinand Marcos, whose 1972-1986 regime was characterized by martial law and synonymous with arbitrary arrests, detention, disappearances, as well as extrajudicial killings.

In an October survey conducted by pollster Social Weather Stations, Marcos Jr. was the most preferred presidential candidate with 47% of respondents picking him.

A Marcos Jr. presidency would offer broad continuity on economic policy, promote foreign direct investments and emphasize infrastructure development, said Peter Mumford, practice head for South and Southeast Asia at risk consultancy Eurasia Group.

But compared with Duterte, he's likely to pursue "more balanced ties" with the U.S. and China, Mumford wrote in a recent report.

Marcos Jr. and Duterte-Carpio agreed to be running mates in the elections, even though the president and vice president are elected separately in the Philippines.

But Duterte has reportedly said that he would not support Marcos Jr.

Leni Robredo

Leni Robredo is the sitting vice president after narrowly beating Marcos Jr. for the position in the 2016 elections. But she has no say in the Duterte government after resigning from her cabinet position in December 2016.

A human rights lawyer, Robredo has been a staunch critic of Duterte's drug war which has killed thousands of people.

Robredo has "carved herself as the genuine anti-Duterte candidate," said Aries Arugay, visiting fellow at think tank ISEAS-Yusof Ishak Institute and political science professor at the University of the Philippines Diliman.

"If some do not really like the changes that have happened under the Duterte administration, then Leni Robredo provides that comfort or that idea that Philippine politics could be normalized post-Duterte 2022," Arugay said earlier this month at a webinar organized by think tank Center for Strategic and International Studies.

In the October survey by Social Weather Stations, 18% of respondents chose Robredo as their preferred presidential candidate — second only to Marcos. Jr.

Francisco 'Isko Moreno' Domagoso

Francisco "Isko Moreno" Domagoso is the mayor of Philippine capital city Manila and a former actor.

As mayor of Manila, Domagoso — who's better known by his screen name Isko Moreno — reportedly focused on reducing crime and cleaning up the streets. He also earned praise for building affordable housing for the poor.

Fitch Solutions said Domagoso would likely campaign on the notion of a "big tent" government that seeks to include different groups and viewpoints. That could mean maintaining some of Duterte's policies, but discontinuing others such as closer ties with China, said the consultancy.

Manny Pacquiao

Manny Pacquiao is one of the greatest boxers of all time and the only man to hold world titles in eight different divisions. He retired from boxing in September to run for the Philippine presidency.

He's also a two-term congressman and currently a senator. He was leader of the ruling party PDP-Laban, but was ousted in July after challenging Duterte over his position on China and record on fighting corruption, reported Reuters.

Pacquiao has vowed to fight corruption and poverty.