The CWA wants job commitments from T-Mobile and Sprint in exchange for its approval of the merger between the two companies, and it will reportedly not give that approval until both companies make a promise to not make any job cuts after the merger has been completed. According to an analysis done by the CWA, it expects that both T-Mobile and Sprint would end up closing stores after the merger takes places, which would lead to some employees likely losing their jobs and that's exactly what the CWA wants to avoid. Though the CWA doesn't represent a large number of T-Mobile or Sprint employees it does represent some, and it's committed to ensuring that they keep their employment.
Though it's unclear if employees would lose their jobs in light of the completed merger, should it happen the CWA estimates that job losses would reach around 30,000 or more, which is no small number by any measurement. It sent out a memo to both carriers on June 26 running through its methodology for estimating the number of job losses that would occur, which it says would include about 26,000 from the store closures alone while the remaining number would probably come from store overlap in the headquartered cities of both carriers - Seattle, WA and Overland Park, KS.
Though both T-Mobile and Sprint have stated during their official announcement that the merger would actually end up providing more jobs as a combined company than the two companies did separately, the CWA highlights that both carriers have a history of closing down U.S. call centers, suggesting that it's rightfully concerned about any job losses that may be a result of the merger. The CWA (the Communications Workers of America) is most recently known for spearheading a movement by AT&T employees regarding fair workplace compensation that ended up with many employees going on strike for a period of time, so it should be no surprise to see the organization going to bat for the employees of the country's two smallest major wireless carriers.