IIS concurrent handling of request slow

In IIS, I have set the "Maximum worker processes" to 16 in application pool setting. Now, I have a request which will load for some time. At the same time, if another request is submitted, this request will not respond until the previous request finished loading. I am curious that I already set the worker process to 16. Is that supposed that IIS will handle the request concurrently with the available worker process? But as I observed, the latter request have response only after the previous request finished. Is that the requests are queued in only one worker process so that make it waiting? How can I make IIS handle the request concurrently without the waiting?