The Samsung Galaxy S10 line continues the recent tradition of having an additional hardware button that activates the Bixby virtual assistant out of the box. However, unlike previous flagship generations, users will be able to re-assign the functions of this button. This new feature may also be transferred to the Note 9 and older phones in the future.
https://www.notebookcheck.net/The-Bixby-button-is-remappable-in-the-Samsung-Galaxy-S10.410638.0.html