Yii2 runAction() returns blank page

I need to call and action from another one. So, I use


Yii::$app->runAction('controller/existing-action');

but it returns a blank page.

If I use:


Yii::$app->runAction('controller/non-exists-action');

Yii2 throws error 404 not found. So, ‘existing-action’ is a valid call.

Therefore, why on the first case I get a blank page?

It was a problem related about the view on the target action ::)