You said your MacBook Pro has been kept for a month idle, so your battery must be drained and the first thing you need to do is to charge your MacBook for a long time till it has enough power to turn on.
If your MacBook is not turning on after you charge it for a long time, you can take the following ways to troubleshoot.
Method 1. Check the power connection.
Check whether your power cable, power adapter, or MacBook port is intact. If they are, your MacBook Pro can't be charged even if you charge it for a moment. You can connect the power adapter to another MacBook, or change to another power cable or power adapter.
Method 2. Disconnect all external devices.
A faulty accessory might prevent your MacBook Pro to turn on. Usually an accessory with wrong contacts, short circuits, or consuming an unusual amount of energy. So unplug all external devices on your MacBook and then press Touch ID or the power button on your MacBook again.
Method 3. Perform a power cycle
This way only works for Intel-based Macs. Hold on to the power button or Touch ID for 10 seconds to force cut the power and force restart your MacBook.
Method 4. Reset SMC
System Management Controller controls the entire MacBook Pro power-on process. Resetting SMC to check whether the problem is with the SMC that makes your MacBook Pro won't turn on.
Method 5. Check your display.
Sometimes, you turn down your display brightness to the lowest by mistake which causes you don't see the images or videos on your screen. Press F2 on your keyboard to adjust the brightness.
Method 6. Get the repair services.
If all the above methods cannot help you to turn your MacBook Pro on, you need to send it to the Apple Store, Apple Authorized Service Providers, or other workshops to repair your computer.
