Duterte's positions was seen to have resonated with older, working class Filipinos, particularly his promise to eliminate the wide-scale drug menace of the country and his harsh stances on crime in Davao City, which he served for more than 22 years, and corruption.

Duterte's campaign also emphasized an anti-establishment tone, accusing political elites based in Manila of not doing much to solve problems in a move that was described as populist.

In his speech during the change-of-command ceremony of the Philippine National Police, then-candidate Duterte credited former president Fidel Ramos as his inspiration.

[5] Early in 2015, Duterte hinted to the media of his intent to run for the presidency in 2016, with the promise of abolishing Congress in favor of a parliament should he win.

[17] In August, while at a meeting with military officers, Duterte spoke with Communist Party of the Philippines (CPP) founder Jose Maria Sison.

[18] On September 7, 2015, in a press conference held at Davao City, Duterte declared he would not be running for president in 2016 and apologized to all of his supporters on the decision.

[19] Mixed reactions erupted on social media hours after the declaration and several supporters still continued to petition online, urging the mayor to revert his decision.

[20] On September 26, 2015, a large number of supporters gathered at the Quirino Grandstand in Rizal Park, Manila, to urge Duterte to run for the presidency in 2016.

[27] On October 13, 2015, in a press conference held at a local hotel in Davao City, Duterte finalized his decision not to run for the presidency, with his daughter Sara's objection being pointed out as one of the main contributors.

[42] Comelec chairman Andres Bautista, in an interview on November 3, stated that although they have noted Diño's withdrawal, they would not move with any further action with regards to a possible substitution until they had Duterte's consent and unless it would be made official with a COC and a certificate of nomination and acceptance from PDP–Laban.

[44] On November 21, in a gathering held in his alma mater San Beda College, Duterte announced his presidential bid and also finally accepted Alan Peter Cayetano's offer to be his running mate.

[45] Duterte said he was disappointed over the decision made by the Senate Electoral Tribunal (SET) regarding Grace Poe's citizenship as well as the current administration's handling of the 'laglag-bala' issue.

[47][48] Duterte topped all other presidentiables including former front-runner Grace Poe in a survey published November 25 and held by Pulse Asia.

[50] On November 29, 2015, the supporters of Duterte and Cayetano held an event named "MAD for Change: Tunog ng Pagbabago" (lit.

[51] On November 30, the PDP–Laban declared Duterte and Cayetano as the party's standard bearers and launched their campaign in a gathering held in Century Park Hotel in Manila.

He noted that law depicts the matter in terms of religious doctrine and intermingles secular marriage with sacramental holy matrimony, which traditionally is only between one man and one woman.

[71] Duterte proposes the creation of designated "business islands" as economic zones to encourage foreign investment and create jobs.

[72] Duterte, contrary to current Philippine government policy, has said he is open to bilateral talks with China when it comes to the maritime dispute centered on the Chinese claim to the Spratly Islands.

[74] He has also said that the Philippines should revert to the previous position to agree to explore jointly the disputed areas with other countries like China, Vietnam, Malaysia, Brunei and Taiwan for resources such as oil, gas and other minerals.

[77] On December 21, disqualified presidential candidate Rizalito David of Ang Kapatiran party filed a petition before the commission to declare Duterte's substitution for Diño null and void.

[79] Another presidential aspirant Roy Señeres also opened the possibility he would allow Rodrigo Duterte as his substitute candidate if he will abide in three conditions, particularly being an opponent of women's right to abortion care.

[85] On December 22, JP Delas Nieves, chairman of the UP Diliman University Student Council, filed the third disqualification case against Duterte before the COMELEC.

[86] In a decision issued February 3, 2016, the COMELEC's first division unanimously denied all filed disqualification petitions against the presidential candidacy of Duterte due to lack of any merit.

During a campaign rally in Ubay, Bohol, Duterte's camp showed a letter coming from the Vatican's Secretariat of State, signed by Giovanni Angelo Becciu dated February 24, stating that Pope Francis has received his letter and that the Vatican appreciates Duterte's apology after cursing Pope Francis in public.

[96] During a campaign event on April 17, 2016, Duterte made controversial remarks about a rape that occurred during a hostage-taking incident in Davao City in 1989.

[110] Duterte also criticized Goldbert and Gorely for their response, and urged the United States and Australia to cut ties with the Philippines if he was elected president.

[115][116] The administration of Benigno Aquino III warned voters that they should be alarmed that Duterte may be involved with the Communist Party of the Philippines and its militant wing the New People's Army.

[118] On April 27, 2016, vice presidential candidate Antonio Trillanes claimed that Duterte had a bank account worth ₱211 million that he did not declare on his legally mandated statements of assets and liabilities.

[124] Documents from Antonio Trillanes claim that the Duterte political family owns properties around Davao City, elsewhere in Mindanao and also in Metro Manila, none of which were revealed by the mayor in his statement of assets and liabilities and net worth.

Senatorial candidates may still make an appearance in the campaign rallies of Duterte and Cayetano to speak depending on availability but PDP–Laban clarified that there won't be any endorsement to any person running for Senator.