In 2017, McCain was diagnosed with primary glioblastoma, a type of brain tumour, and was operated upon to remove a blood clot, in Phoenix, Arizona.
The Arizona Senator who ran unsuccessfully for president against Barack Obama in 2008 was a frequent critic of President Donald Trump, as well as a target of his attacks. My thoughts and prayers are with his family. They will recall his efforts with the late Senator Edward (Ted) Kennedy and others to achieve a resolution of the position of out-of-status immigrants, including the Irish, in the United States.
Bush says in a statement that McCain was a "public servant in the finest traditions of our country" and is calling him a "friend whom I'll deeply miss".
Near the driveway to his ranch in a rural part of Sedona, Arizona, a sign read "Sen McCain, thank you for your service". "Our hearts and prayers are with you!" he added. But all of us can aspire to the courage to put the greater good about our own.
The Philippine government on Sunday joined the worldwide community in mourning to the passing of United States Sen.
George Bush said, "Some lives are so vivid, it is hard to imagine them ended. John McCain. We appreciate everything McCain has done for our country".
From his selfless service in uniform to his time in Congress fighting for those who serve and have served, Senator McCain dedicated his life to this nation and his fellow citizens.
"Ben Jealous, Democratic nominee for Maryland governor: "I am incredibly saddened to hear that Senator John McCain has passed". A naval aviator during the Vietnam War, he's also well known as a former prisoner of war.
McCain's daughter, Meghan McCain mourned the death of her father in a sentimental Twitter post. "I join all Americans in praying for peace and comfort for his beloved wife Cindy, his family and his friends".
Meanwhile, Foreign Minister Shah Mahmood Qureshi has expressed his condolences on the passing of USA senator John McCain.
North Carolina Congresswoman Alma Adams, who represents parts of Charlotte, called McCain a "true statesman".
Following his death, American presidents, past and present, began issuing statements depicting the man for who he really was, a hero, statesman and an incredibly talented politician.
Earlier this summer, McCain issued a blistering statement criticising Trump's meeting with Russian President Vladimir Putin.