As this Washington Post op-ed says, Alan Gross's involvement in the US rapprochement with Cuba is a subplot that will soon fade away. To me, however, it illustrates the enormous power of Jews in America and the Jewish lobby in Washington. The US embargo on Cuba and related sanctions, including the Helms-Burton Act which I find horrendous, has been in place for decades and attacked by various people and groups for decades, but it took the Cuban arrest of Alan Gross, an American Jew who was working on some sort of spy mission involving Cuban Jews, to break the back of the sanctions. The fact that Alan Gross was exchanged for three high value Cuban spies illustrates his importance and the Jewish influence behind him. The US claimed that the three Cubans were exchanged for an unidentified American spy, not Alan Gross, but the reason the other spy was never identified is because he did not exist. There may have been another spy exchanged, but he was nothing compared to Alan Gross and his importance to the Jewish lobby.
It's not clear to me what Gross's spy mission was. He was setting up a clandestine internet for Cuban Jews, but I don't know if this clandestine connection was for American Jews to use to support Cuban Jews, or was to get Cuban Jews to report information about Cuba to the CIA or some other American group collecting such information. In one case, Cuban Jews stood to benefit from outside contact, in the other they became liable to arrest as spies working for America. The Cubans seemed to view it in the latter light, no matter what the original intent was.
Interestingly, Raj Shah, the head of USAID, resigned shortly after Gross's release, although everyone claimed there was no connection between the two events. Shah was also accused of being involved in two other clandestine activities in Cuba, some kind of hip-hop activity and some kind of twitter set up. The Washington Post article noted above raises the question whether Gross was an unwitting civilian contractor manipulated by USAID. Of course the other question is whether Gross was really a CIA agent operating under USAID cover, or perhaps under the additional cover or some Jewish organization.