To unlock the "MISSION COMPLETE" trophy in Detroit: Become Human, you must allow Connor to be hacked by Cyberlife in the final mission "BATTLE FOR DETROIT". If you break free of the hacking attempt you will get this instead:
You should make sure the following incidents happen on the way to the final chapter to make the requisite scene much easier to reach:
*** Spoiler - click to reveal ***
-- Generally keep everyone alive and happy and the public sympathetic.
-- Make sure Connor finds Jericho in LAST CHANCE, CONNOR...
-- Allow Connor to become deviant and join the Jericho cause in CROSSROADS
-- Have Markus spare Connor in THE NIGHT OF THE SOUL so he goes off to Cyberlife. Markus should choose the peaceful protest approach.
-- Have Connor succeed in hacking the androids in the Cyberlife basement. Note that you can save Hank in this sequence AND convert the androids as long as you choose to spare Hank and then successfully fight your clone, and you talk to Hank about his son (you need to find out his name earlier in the game, when you bust into Hank's house to save him. The son's photo is on the kitchen table).
-- Have Markus successfully conduct a peaceful protest at the camp entrance and survive along with his team-mates. You can sing at the guards to achieve this as long as public opinion is high.
-- Finally, when Connor stands with the Jericho crew during the final speech, you will be whisked off to Amanda's Zen garden. After she disappears, STAY STILL and let the whole scene play out until you shoot Markus in the back. If you attempt to leave Zen Garden by activating the hand-print stone you will void this trophy, and earn MY TURN TO DECIDE instead.
If you follow the steps above you will receive the trophy after the final credits when you reach the flowcharts.
golden_eternity reports that if you are looking to get this later outside of a full playthrough, you can go back to the "Defend the Barricade" checkpoint in "Battle for Detroit", play through from this point and make sure to stay in the Zen Garden.