According to The Wall Street Journal, Dish Network and T-Mobile US are currently considering a merger of the two companies. Discussions of the merger are currently at the "formative stage", although executives from both companies reportedly agree with the plan's big picture.
While a purchase price hasn't been settled on at this stage, if the merger were to go through, T-Mobile CEO John Legere would remain CEO of the new merged company, while Dish CEO Charlie Ergen would become chairman.
T-Mobile is currently the fourth-largest wireless network in the United States with over 55 million subscribers, although strong growth from Legere's "Uncarrier" strategy should see the company overtake Sprint sometime this year. Several companies have attempted to buy out T-Mobile over the years, including AT&T in 2011 for $39 billion in a deal that ultimately failed.
Dish Network is currently the second-largest satellite TV operator in the United States, behind DirecTV, with around 13.8 million subscribers. In recent years the company has acquired significant amounts of wireless spectrum, although this spectrum has essentially gone unused as Dish currently doesn't operate a mobile network.
If Dish and T-Mobile were to merge, T-Mobile could use Dish's wireless spectrum to strengthen their position as a wireless carrier, while both companies could continue to operate their separate services. It's not clear when or if the merger will be approved, but you can add Dish to the growing list of companies interested in partnering with T-Mobile.