In the spring of 2014, after a decade of visa problems, the Hassan family moved out of its spacious house in Karachi, Pakistan, to an apartment in Rosemont, a suburb of Chicago near O’Hare International Airport. They were a family of eight, two parents and six kids, jammed into a three-bedroom space. Money was tight and work unsteady; for most of them, the move was a struggle. But their 15-year-old son, Sumail, was thrilled—being in the U.S. meant less lag time when he played Dota 2.