AT&T has launched its new "5G Evolution" network in select parts of Austin, Texas. According to AT&T, 5G Evolution "offers twice the speeds of (its) 4G LTE network."
Keep in mind that this isn't true 5G, as actual 5G standards have yet to be finalized and wont be official before 2019. AT&T is still using this opportunity "pave the way to the next generation of faster speeds".
For now, only owners of the Samsung Galaxy S8 and Galaxy S8+ can enjoy the faster data speeds offered by AT&T's 5G Evolution. Both of these new smartphones have been available through AT&T and other carriers in the US since last week.
AT&T says it'll soon launch 5G Evolution in other areas across the US, starting with Indianapolis (sometime this summer). By the end of the year, 5G Evolution should be available in over 20 major metropolitan areas stateside, including Atlanta, Boston, Chicago, Los Angeles, Nashville, and San Francisco.
source - AT&T