Horizon Zero Dawn is coming to PC in summer of 2020 and it has a Steam page to prove it. That Steam page features some screenshots, most of them stamped with the words "Captured from a PlayStation 4 Pro". Except for one, suspiciously wide 3440×1440 image. Click the top-right of that image to embiggen it.
When asked if Horizon Zero Dawn would have ultra-wide support, Guerilla Games' Community Manager Anne van der Zanden replied in the affirmative and confirmed that the screenshot was from the PC port.
It'll also have Steam achievements, but cloud support hasn't been confirmed yet. "More details will be released at a later date!" apparently.
After playing Breath of the Wild I never want to shoot a bow with a controller again, so none of this really matters as long as I get to light up the weak spots on dinosaur robots with a mouse. But if you're hanging out for ultrawide support and cheevos, there you go.