T-Mobile US Inc (TMUS.O) on Monday said it will acquire the wireless operations of UScellular (USM.N) for $4.4 billion in cash and assumed debt, a deal that will expand the telecom giant’s 5G network reach and customer base, particularly in rural areas. The acquisition will see T-Mobile, the second-largest U.S. wireless carrier, absorb UScellular’s 4.2 million wireless customers and certain spectrum assets covering around 21…