Hunter Hunted (Fallout 4)

Hunter/Hunted is a quest and achievement/trophy in Fallout 4.

Quick walkthrough
Travel to C.I.T, track and kill the Courser in order to take his chip.

Detailed walkthrough
Upon getting the quest, travel to the C.I.T. ruins north of Diamond city. The "Courser Signal" will be available on the Pip-Boy's radio at that point, tune to it and follow the signal east to Greentech Genetics.

Greentech is filled with Gunners who are fighting the Courser. As you enter the building, the commander of the Gunners starts issuing orders over the intercom, he orders half of his troops to retreat up the building as the Courser advances on them and the other half to engage you. You have to fight your way up through the building. The Courser is just ahead of you the whole time, his fights with the Gunners can be heard in the distance. Once you get the to seventh floor, there is an elevator that takes you up to the top of the building.

Once there, the Courser can be heard threatening some Gunners for a password, they refuse to give it to him and he kills them. Approach him and he'll ask what you want, shortly afterwards he will engage unless you got his deactivation code from Mama Murphy. Once the fight is over, you can loot the Courser chip off his body and the quest is complete.

After the fight, you can see a woman locked in the room that the Courser was trying to gain access to. She asks you to retrieve the password to the door that one of the Gunners stashed in a nearby toolbox. Once she is let out, she tells you that the Courser was after her and the Gunners were hired to protect her as she travelled across the Commonwealth