switch
as a field type.
array(
'name' => __( 'Field Name', 'cmb2' ),
'desc' => __( 'Field Description', 'cmb2' ),
'id' => 'your_switch_button',
'type' => 'switch',
'default' => 0,
'disabled_warning' => true, // switch between gray and red button style for disabled.
'label' => array('on'=> 'On', 'off'=> 'Off')
),