First, you need to purchase the human skill, Combat Focus (2 - Neuromods). After obtaining this, equip the ability to your weapon wheel where you'll be able to activate it with
. To get the trophy, you must kill an enemy while it's active. Combat Focus only lasts for 10 seconds, so the easiest way to do this is to activate it near a mimic and shoot that mimic with your shotgun, since most times, mimics are one shot kills.
Killing an enemy with Combat Focus activated will get you this trophy.