Like all Present Perfects, the Present Perfect Continuous links an action in the past with the present time. In English, there are two main uses of the Present Perfect Continuous (also called Present Perfect Progressive).
1. We use the Present Perfect Continuous when we want to emphasize how an action that started in the past has continued without stopping until now and is still taking place.
So, for example, if you're in a doctor's waiting room, you can say:
"I've been waiting for fifteen minutes."
You've been waiting for fifteen minutes and you're still waiting now.
2. We use the Present Perfect Continuous for an action that happened in the recent past (a short time ago), and we can see the result of that action now in the present.
So, for example, if someone looks unhappy and their eyes are red, you might say:
"She's been crying."
She's not crying now, but we can see the result of the crying, which happened a short time ago.