2017
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The first year of Trump's presidency was marked by a heated back-and-forth as North Korea tested more than a dozen missiles, prompting Trump to respond, often on Twitter. Trump famously referred to Kim as "Little Rocket Man" at various times both on and off the internet.
Swelling tensions reached a new high on Aug. 9, 2017, as North Korea threatened a strike on the U.S. territory of Guam in a statement distributed by its state-run news agency. The country said its military was reviewing a plan to create an "enveloping fire" around Guam, 2,100 miles from North Korea.
Icy relations and missile tests continued, with North Korea claiming in late November that it had a nuclear-capable intercontinental ballistic missile that could reach the entire continental U.S.
2018
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But things began to change in 2018 amid an apparent larger shift in North Korean foreign policy. These are some of the key events from 2018 so far:
March 7: A top South Korean official visits Pyongyang and says Kim is willing to discuss the fate of his nuclear arsenal with the United States and expressed a readiness to suspend nuclear and missile tests during such talks.
March 9: Trump accepts Kim's invitation to meet, which White House initially says will take place by the end of May.
March 27: Kim makes a surprise visit to Beijing and meets Chinese President Xi Jinping in an apparent move to strengthen his leverage ahead of negotiations with Trump.
April 18: Trump confirms that Mike Pompeo, then the CIA chief, had met secretly with Kim in North Korea and said "a good relationship was formed" heading into the adversaries' anticipated summit.
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April 21: North Korea says it has suspended nuclear and long-range missile tests and plans to close its nuclear test site as part of a shift in its national focus to improving the economy. Trump tweeted, "This is very good news for North Korea and the World" and "big progress!"
May 9: Pompeo, now U.S. secretary of state, makes an unannounced one-day trip to Pyongyang to prepare for the planned Trump-Kim summit. North Korea releases three Americans who had been imprisoned, and they return with Pompeo to the U.S.
VIDEO: Who are the detainees released by North Korea?
Kim Dong Chul, Tony Kim and Kim Hak Song: Who are the detainees released by North Korea?
May 10: Trump announces he will meet with Kim in Singapore on June 12. He tweets: "We will both try to make it a very special moment for World Peace!"
May 12: North Korea says it will hold a ceremony to dismantle its nuclear test site between May 23 and 25 and foreign journalists will be invited to attend.
May 24: Trump calls off the planned summit, calling the cancellation a "tremendous setback" for peace and stressing that the US military was ready to respond to any "foolish or reckless acts" by the North.
June 1: Trump announced that his historic summit with Kim is back on for June 12 in Singapore. Trump made the announcement, just a week after he canceled the summit, after an hour-long meeting with a top North Korean official who delivered a letter from the North Korean leader.
The Associated Press and ABC News contributed to this report.