Mac won’t power on

1. Make sure that your Mac is connected to AC power. If it doesn't have a built-in display, make sure that your external display is connected to power, connected to your Mac, and turned on.
2. Press and hold the power button on your Mac for at least 10 seconds, then release.
3. Every Mac has a power button. On notebook computers that have Touch ID, press and hold Touch ID.
4. If you see no change on your Mac, press and release the power button normally.
5. If your Mac now turns on but stops at some other screen during startup, follow the steps for when your Mac doesn't start up all the way.

If your Mac still doesn't turn on, please contact Apple Support.

What model-year 15-in MacBook Pro?

what does it do if you leave the power adapter directly connected for a while? will it power up then?