ALEX LOCKIE for Business Insider Australia has written an excellent article, of June 23, 2017 concerning feelings of North Korea's Kim Jong Un that he is under threat of assassination by foreigners. Article begins:
“The US and South Korea reportedly have a special ops team 'to take out Kim Jong Un"
"Even though he’s the supreme leader of his country, Kim Jong Un has reportedly been living like a hunted man out of fear that the US and South Korea are collaborating on a special forces team to take him out in case of a contingency.
South Korean intelligence services told lawmakers recently that the moves of US and South Korean forces make Kim “extremely nervous,” according to the Korea Herald. Apparently, Kim has been riding in his subordinates’ cars and making fewer public appearances.
In March, South Korean media reported that the US Navy’s SEAL Team 6, the same group that pulled off the 2011 raid that killed Osama Bin Laden in Abbottabad, Pakistan had arrived in South Korea for a joint-training exercise.
...The US would not confirm the presence of Navy SEALs in South Korea, but it did announce the arrival of the USS Michigan, [an Ohio-class SSGN] submarine that sometimes carries special operations forces.
See whole Business Insider Australia article.
Given Kim would have 10s to 100s of close-in bodyguards, deep bunkers in mountains and protected by (the outer concentric circle of) the whole North Korean military - it is unlikely that the US would attempt to insert a few gun toting CIA/Special Forces/SEALS to take Kim out.
More likely is the use of a huge bunker busting, GPS programmed bomb  (see photo and diagram below) or missiles to hit Kim in a fixed or moving position.