(CNN)The journey of Americans released from Iran is far from over.

From the future of U.S.-Iranian relations to the fate of another missing American, Sunday’s release could mark just the beginning of more political maneuvering to come.

Here’s the latest on the prisoner swap and what’s next:

Which Americans were freed in the swap?
Washington Post journalist Jason Rezaian, Marine veteran Amir Hekmati, Christian pastor Saeed Abedini and Nosratollah Khosravi-Roodsari were released as part of a prisoner swap.

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Former Iranian prisoner: I'm elated for Jason Rezaian

Former Iranian prisoner: I’m elated for Jason Rezaian 05:02
Iran detained Rezaian in 2014, eventually charging him with espionage and other crimes, according to The Washington Post. He was the newspaper’s Tehran bureau chief.

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Hekmati was detained in 2011, weeks after arriving in Iran to visit his grandmother, according to his family’s website. The former Marine infantryman and Arabic and Persian linguist was accused of espionage and other charges in 2012.

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Abedini, an Iran native and convert to Christianity, was arrested in 2012 and convicted the next year on charges of attempting to undermine the Iranian government. He had been sentenced to eight years in prison.

Not much is known about Khosravi-Roodsari.