The OnePlus 5 has a wide-range of supported bands for LTE. There are 34 supported here, making it a world phone. But one thing that Verizon and Sprint customers will notice is the fact that there is only support for one CDMA band. Which makes this somewhat compatible with Verizon and Sprint networks, but not quite there. Meaning that if you want full support, you'll be stuck using the OnePlus 5 on AT&T and T-Mobile's networks. This has been the case for OnePlus' previous smartphones as well, so this should come as no surprise.
For FDD LTE, bands 1, 2, 3, 4, 5, 7, 8, 12, 17, 18, 19, 20, 25, 26, 28, 29, 30 and 66 are supported. On TDD LTE it's bands 38, 39, 40 and 41. TD-SCDMA gets bands 34 and 39 supported and WCDMA gets bands 1, 2, 4, 5 and 8. CDMA EVDO has BC0 and the usual GSM 2G bands are here, 850, 900, 1800, 1900.
To the untrained eye, what this means is that Sprint's three LTE bands (25, 26 and 41) are all supported, and two out of Verizon's three bands are supported (2, 4 and 13). For AT&T and T-Mobile, all of the bands are supported. That's bands 2, 4, 12 and 17 for AT&T and bands 2, 4 and 12 for T-Mobile. So this smartphone would (at least in theory) work on Sprint, but you would only have LTE coverage. So what that means is that if you go to an area that does not have LTE and is still stuck on 3G – which is Sprint's CDMA network – you will drop down to GPRS, if you get any coverage at all. The same will be true for Verizon, but since band 13 isn't included, you won't get good indoor signal either since band 13 is Verizon's 700MHz C-block spectrum.
So as expected, this is still, for intents and purposes, a GSM smartphone from OnePlus. That's about what everyone expected, although it would have been nice to see this available for Sprint and Verizon customers as well. If you are on AT&T or T-Mobile it will work as expected. Although you may miss out on some carrier features like VoLTE and HD Voice – although OnePlus does typically build that into its smartphones. And if you travel to other parts of the world, perhaps Europe or Asia, you'll still be covered and be able to use your OnePlus 5 with ease – since it's dual-SIM, you can leave that other SIM card inside with your normal SIM card.