Currently the best performing mobile chipset is definitely the latest Apple A11 Fusion, which pretty much dominates in both single and multi-core tests. One of the leading chipset manufacturer, Qualcomm, is now rumoured to unveil its flagship chipset much earlier than anticipated.
The new Snapdragon 845 is expected to be announced at the Snapdragon Technology Summit in December. The event is scheduled for December 4-8 and is to be held in Maui, Hawaii. While it might be announced then, it will take some time before it launches. One of the first phones to get it should be Samsung Galaxy S9 lineup.