Certain versions of the Samsung Galaxy Note 4 already rooted, courtesy of Chainfire
One of the most renowned and notable among them is Chainfire, the person who is responsible for rooting a whole galaxy of smartphones over the years. Usually he wastes no time and develops a rooting method for a particular device in no time, and certain Asian variations of Samsung's phablet - SM-N910C, SM-N910U, and SM-N9106W - are no different, as they have already succumbed to Chainfire's adept rooting skills. Chainfire assured the potential adopters of the phablet that a rooting method for the remaining version of the Note 4 will be released shortly after the device arrives on the market.
However, this method will still trigger the Knox warranty of your Note 4 from 0x0 to 0x1, which might (or might not) give you some hard time in case you need to take advantage of your device's warranty. Let us refresh your memory - the Knox warranty is a single-time programmable e-fuse, which goes off if you root the device or flash a non-stock firmware, kernel, etc. At the moment, there's no way to reprogram that e-fuse and prevent the Knox warranty from being voided.
source: @Chainfire (1), (2) via GSMArena