I believe both Android and iOS support SHAKEN/STIR, as long as your carrier supports it. On my phone, at least, I see Caller IDs tagged with "likely spam" if a check fails.
But it is great, when someone calls and i don't have them in my address book they show me the name of them, for example the name of the doctor offices, companies etc. As you can see in the demo carousel on their page, it shows "SMART" next to it, which emphazises that this isn't a number in your contacts but fetched from the internet.
Or if they are likely spam, my whole display is red and i can immediately hang up.
I wonder if this is a rollout thing -- I had AT&T for years, and towards the end (about a year ago) I began receiving spam notices. But I was in one of their "primary" markets, so it's possible they rolled it out first here.