Add Campaign Manager capabilities to Editor role

function.php

add_action(
	'init',
	function() {
		$campaign_manager = get_role( 'campaign_manager' );
		$editor           = get_role( 'editor' );

		foreach ( $campaign_manager->capabilities as $cap => $has_cap ) {
			if ( ! $has_cap ) {
				continue;
			}

			if ( ! $editor->has_cap( $cap ) ) {
				$editor->add_cap( $cap );
			}
		}
	}
);