You mean that your MacBook Pro can't boot up but you hear the fan's running noise, right? This a tricky MacBook not turning on issue. And it's right to reset SMC as SMC controls fans, lights, power functions, etc. on your Mac.
Disconnect useless external devices: This is to exclude certain peripherals making your Mac won't turn on.
Reset NVRAM: NVRAM maintains the system-related preference configurations. It is used to prompt your Mac to start up properly. So, resetting it may help boot up your Mac.
Shut down your Mac completely and then turn it on: Maybe unknown software errors appear to confuse your Mac to turn on and off. You can press the Touch ID for 10 seconds to completely turn off your MBP and wait a moment, then turn your MBP on.
Contact Apple: If your Mac still won't turn on but with the fan running, contact the Apple support team to help you.