Apple Watch with cellular

Yes.

The Apple Watch shares the iPhone's number. Carriers that support the Apple Watch charge approx $10 U.S. to share the number between the iPhone and Apple Watch.

Here is a list of carriers that support the Apple Watch: Apple Watch - Carriers - Apple

There is the Apple Watch Family Sharing, where your Apple Watch is treated as if it belongs to a dependent child, and is totally controlled by the parent's iPhone. That is to say, and iPhone is still required, AND the Apple Watch has less functionality, and someone else is able to control your Apple Watch.

Set up Apple Watch for a family member - Apple Support

Set up a family member’s Apple Watch - Apple Support

Yes, but only to set it up. After your cellular watch is set up you can use it to communicate without your iPhone nearby. Personally, I think the iPhone and watch work very nicely together.

Koriwoods86 wrote:

Do I have to have an iPhone to use my Apple Watch with cellular?

You always need an iPhone to set up an Apple Watch, cellular or not.