He made a decisive vote a year ago that killed Republican attempts to repeal Barack Obama's health care reforms, and Trump never forgave him.
A senator for Arizona for more than three decades, McCain had been suffering from glioblastoma, a brain cancer, since July 2017 and had not been at the U.S. Capitol this year. Last Friday it was announced that he discontinues treatment. "Kathryn and I join a grateful nation in keeping his wife, Cindy, and the entire McCain family in our thoughts and prayers".
Mr McCain's wife Cindy said she was heartbroken by the death of an "incredible man".
"Ben Jealous, Democratic nominee for Maryland governor: "I am incredibly saddened to hear that Senator John McCain has passed". Former rivals and Presidents Barack Obama and George W. Bush had been asked to give eulogies, people close to both former presidents and a source close to the senator confirmed to CNN.
Trump, who shared a rocky relationship with McCain tweeted, "My deepest sympathies and respect go out to the family of Senator John McCain".
McCain spent over five years as a prisoner of war in Vietnam, was a Navy Senate liaison, served in the House of Representatives, and replaced conservative icon Barry Goldwater in the Senate, a seat he held for over 30 years.
Speaker Paul Ryan also in a tweet said: "John McCain was a giant of our time - not just for the things he achieved, but for who he was and what he fought for all his life. Another American maverick and warrior, General George Patton once observed: We should thank God that men such as these have lived". "But, to me, more than anything, John was a friend".
Memorial service honoring US Sen. John McCain set for Thursday
Though arrangements were incomplete this morning, multiple reports said McCain asked former presidents Barack Obama and George W. Following the service, McCain will lie in state for the remainder of the day and the public will be invited to view his casket.
Senator Jerry Moran issued a statement, calling McCain "a true American hero, whose sense of duty to our nation led a lifetime of public support".
Meanwhile, Foreign Minister Shah Mahmood Qureshi has expressed his condolences on the passing of USA senator John McCain.
During the 2016 presidential campaign, Trump mocked McCain for being captured and tortured during the Vietnam War, saying that McCain shouldn't be looked at as a war hero.
She continued: "He was a tough politician, a trusted colleague, and there will simply never be another like him".
"John McCain was a man of deep conviction and a patriot of the highest order". "Cindy and the McCain family have lost a loving husband and father". Sources quoted by U.S. media said Mr Trump would not be invited to the funeral and the current administration would probably be represented by Vice President Mike Pence.
Senate Majority leader Addison Mitchell McConnell described Senator McCain's life as a "bright example" in a world filled with cynicism about national unity.