Flickerstep is a Unique Boots in Diablo IV Season 15 for All classes. It comes from General Unique Pool - every Lair Boss (Initiate, Greater, Exalted, Belial) can drop it in addition to their dedicated table.
Unique power
Each enemy you Evade through reduces your active Ultimate Cooldown by [3.0 - 4.0] seconds, up to 10 seconds.
Affixes
Primary Core Stat
Attacks Reduce Evade's Cooldown
Where it drops
General Unique Pool - every Lair Boss (Initiate, Greater, Exalted, Belial) can drop it in addition to their dedicated table