To unlock the "COMPLIANT" trophy in Detroit: Become Human, you must choose to remain on your mission when confronting Markus during "CROSSROADS".
*** Spoiler - click to reveal ***You can do this without killing Markus, if you are also trying to get end-game trophies for Markus' story. Assuming you have come up to this point keeping Connor as compliant to his orders as possible, the option to turn deviant may even be blocked out. Choosing to "Remain a machine" in this moment does not lead to Connor killing Markus. Later on in the chapter you get another scene with Connor where he is confronted by a soldier who does not realise Connor is on his side. If you choose to run from the soldier he will kill Connor, which allows Markus to escape in turn.
You should follow the options in the spoiler tags above if you are using this play-through to also go for any of Markus' end-game trophies (including SURVIVORS) and also if you are going for:
Making this decision has a severely detrimental effect on your ability to get this trophy: