Much of the Google use of liquid chillers was protected behind NDAs as part of its "hidden advantage" with respect to the rest of the world. It was the secret behind really low PUE numbers.
Do we know if other hyperscalers also use liquid chillers to achieve very low PUE values? I think I saw photos from xAI's new data center and there was liquid cooling.
I don’t know of any Co-lo types that did it, Microsoft had some creative ideas about things like that but I don’t know if they brought any to fruition. I suspect there are still opportunities there.