The The Assignment Add-on for The Evil Within has 10 achievements.
Clear Chapter 1, "An Oath."
Lure an enemy with a phone call and lock them in a room. (Ch. 1)
Use a single trap to kill two or more enemies in The Assignment. (Ch. 2)
Survive the duel without using any electronic devices in the environment. (Ch. 2)
Get a Cadaver to grab and kill a Haunted. (Ch. 2)
Clear Chapter 2, "Crossing Paths."
Collect all Research Documents in The Assignment.
Collect all Personnel Files in The Assignment.
Complete the hidden letter in The Assignment.
Clear The Assignment in KURAYAMI Mode.