I make this flow to responsing on powerapps, but I am getting nothing...
Can you show us the Run command in Power Apps that invokes the Flow? You have to use a Run command or Power Apps won't be waiting for a response.
Another common issue happens when you add the Respond to Power Apps after you've already saved the flow and added it in Power Apps. To update the definition in Power Apps you need to remove it and re-add it.
Sorry for the mistake...I put on communty PowerApps.