To open the boom gate in Chapter 11, you must solve a puzzle together with Hugo and Sofia's help.
A Plague Tale: Requiem – Chapter 11 – How to open the gate in the subway – Puzzle walkthrough
In Chapter 11, The Cradle of Centuries, you will come across a huge gate that you must open to progress in the story. This will block your progress, and to continue you must solve a puzzle that opens the gate.
Let's find out how you can solve it.
At this point in the story you will be with Hugo and Sofia. To open the gate, you need both of their help. Inside this huge room you will find wheels, levers and other things that you need to interact with.