Passing $form_state data into \Drupal::entityQuery('user')
Does $selectesRole have the expected value? I'm pretty sure you want to use $form_state-&gt;getValue('bulk_perfplans_roles') instead. Details here. 

Also is it a single value field? You may need to pass an additional IN parameter to your field condition and do some additional prep if the result from getValue is an array. 

Also make sure you're passing the machine name of the role and not the label.