Is it an LTE model or just bluetooth? I believe that you can get some functionality via LTE, provided you do the initial setup using an iPhone, but the models without that there's essentially nothing you can do.
Apple is a walled garden. They deliberately use proprietary methods rather than open standards, and part of that is because it sells extra product to their own users (if you have an Apple phone you can do things between it and an Apple Watch or Apple Tablet that you can't easily do with other brands), and partly because it locks users in (if you have an Apple Watch it loses most of its functionality if you switch your phone to Android). That latter is also why iMessage remains iOS-only (internal discussions which confirm this were unveiled a few months ago), why Apple refuse to allow RCS messaging on their phones, and frankly I'm pretty sure it's why iPhones will never use USB-C (the idea that in a few years time they'll remove all ports and force owners to use their proprietary, Apple-only wireless chargers, seems however sadly plausible).
To be fair I have a lot of problems with Google and their business model too, but they are different problems from those I have with Apple. I'm just realistic: both corporations act in their interests (as they perceive them) and not yours or mine. And to show that this isn't anti-Apple prejudice I do have a couple of Apple devices - I prefer to use whatever device suits my needs best, but also never to become dependent on any proprietary feature (because that's how they lock you in). So mixing devices from different systems is how I prefer to work, but in the case of the Apple Watch that's not really an option, it is very much designed only to work with an iPhone, and I'm sure the fact that this locks users into iPhone ownership is a big part of its role for Apple.