I do terrestrial point to point microwave/millimeter wave stuff professionally, so it depends what you're trying to search for. Microwave isn't really used for any significant portion of traffic at "long distances" anymore, like it was in the days before singlemode fiber. But it very useful in places where you want to reach a very rural area or go somewhere that would be cost prohibitive to build to with fiber.
There are atmospheric and practical effects that make going more than 50-60km with PTP microwave, and data rates above 700-800 Mbps, increasingly costly as the distances increase.
It is totally possible technologically to build very long chains of many microwave PTP radio hops, as some high frequency trading companies set up between new york and chicago, but the aggregate throughput and capacity is minuscule compared to fiber.
Would be happy to answer any more specific questions.
Here's an example of a current state of the art point to point microwave radio, for use in the common FCC licensed part 101 bands (6, 11, 18, 23 GHz, etc)
> where the best in class now is radio links generally
What would I put into a search engine to learn more about these more recent long distance radio links? Thanks!