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T-Mobile USA uses UMTS 3G bands 2 and 4 as well as LTE bands 2, 4, 12, and 66 most commonly. Band 71 is the future of T-Mobile's LTE deployment currently so expect that to be more common over the next few years.
Can you tell us exactly what devices you are bringing? We'd need to know the exact model number (e.g. not "Moto G5S" but rather XT1793, XT1794, etc.)