Is there any entry in the control panel for the cameral at all?  If not, it's time to check the connection between the camera and the system board.  Service manual linked below.

Support (by phone or email) ends with the warranty -- and since the warranty on this system is almost certainly expired, you'll need to open a support ticket with Dell by paid incident at this point.

Service manual is here:

https://www.dell.com/support/home/en-us/product-support/product/xps-15-9570-laptop/docs

 

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@Sub01 wrote:

Dell didn't even upload the camera driver to their website! 

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That is as expected. Dell has not distributed camera drivers through their site for several years. Under Windows 10, camera drivers are provided by Windows Update. 

If your camera doesn't work after installing Windows 10 and running Windows Update (and checking in options for driver updates), look in in Device Manager under Imaging devices or Cameras.
Is a device listed there? If it is, there must be some reason why Windows Update isn't providing the driver.

In Device Manager you can right-click the device, uninstall it and then reboot and run Windows Update to see if that fixes it. You can also choose to update the driver from Device Manager.

If needed, in Device Manager you can right-click the device and under the Details tab you can find Hardware IDs that you can search for to help to identify the device. 

Find the manufacturer name of your camera. If you don't know, tools like Speccy or Belarc Advisor may be able to identify it. You may find drivers on the manufacturer's web site.

EDIT: ejn63n posted as I was typing. If your camera isn't seen at all in Device Manager or tools as I mentioned, you'd better open up the laptop to check the hardware as he suggested.