Can a MacBook Pro be updated beyond macOS 10.10.5?

It depends on the model year of your MacBook Pro.

The model year of a MacBook Pro is available at Apple menu > About This Mac.

Early 2008 through 2009 models can be upgraded to El Capitan 10.11.6. See: https://support.apple.com/en-us/HT211683

A mid-2010 through late-2011 MacBook Pro can be upgraded to High Sierra 10.13.6 but no later version.

A mid-2012 through early-2013 MacBook Pro can be upgraded to Catalina 10.15.7. See: https://support.apple.com/en-us/HT211683

A late-2013 or later can be upgraded to the current version of Big Sur. See: https://support.apple.com/en-us/HT201475

Updates are offered automatically to bring you to the latest fixes for the Major version you are running.

UPGRADES to a higher major version are obtained like a "purchase" on sale for $0.