CNN  —  Undocumented immigrants who’ve been paying taxes in the US are facing an unsettling possibility: This year, that may be used against them. A recent data-sharing deal between the Internal Revenue Service and the Department of Homeland Security is sparking widespread concern in immigrant communities – though some details about how the deal could work haven’t been disclosed. The agreement has left many undocumented immigrants feeling hesitant to pay taxes this year and uncertain about what