Once you put in the xdebug on and off into .lando.yml you can use the path mappings in the attached screenshot to get the debugger working in phpstorm. I needed to setup these pathmappings to get it working.
excerpt from my working .lando.yml
tooling: xdebug-on: service: appserver description: Enable Xdebug. user: root cmd: - docker-php-ext-enable xdebug && kill -USR2 $(pgrep -o php-fpm) > /dev/null || /etc/init.d/apache2 reload - tput setaf 2 && echo "Xdebug On" && tput sgr 0 && echo xdebug-off: service: appserver description: Disable Xdebug. user: root cmd: - rm /usr/local/etc/php/conf.d/docker-php-ext-xdebug.ini && kill -USR2 $(pgrep -o php-fpm) > /dev/null || /etc/init.d/apache2 reload - tput setaf 1 && echo "Xdebug Off" && tput sgr 0 && echo