https://www.techradar.com/news/t-mobile-and-sprint-merger-heres-what-it-means

T-Mobile and Sprint have announced that they intend to merge into a unified carrier simply called T-Mobile. This will put the conjoined company in number three position in terms of subscribers behind Verizon and AT&T.

By joining forces, T-Mobile now comprises of both company’s subscribers, as well as those who use MetroPCS, Boost Mobile and Virgin Mobile.