40 Stat. 411, enacted 6 October 1917
This law doesn't apply to just one country but during the 1950's and 1960's was used in relation to Cuba.
Pub.L. 102-484, 106 Stat. 2315
This 1992 act prohibited foreign-based subsidiaries of U.S. companies from trading with Cuba, travel to Cuba by U.S. citizens, and sending family remittances to Cuba.
Pub.L. 87–195, 75 Stat. 424-2
This was enacted September 4, 1961 and reorganized the structure of existing U.S. foreign assistance programs but §2370 dealt specifically with the embargo of trade with Cuba.
Pub.L. 104–114, 110 Stat. 785
The official name of this law is the Cuban Liberty and Democracy Solidarity Act of 1996 though it is also known as the Libertad Act. It strengthened sanctions against Cuba, codified the U.S. embargo on trade and financial transactions, created a private cause of action and provides a path for U.S. nationals with claims to confiscated property in Cuba to file suit in U.S. courts against persons that may be "trafficking" in that property, etc. (This is a timeline that relates to claims External by U.S. citizens and corporations)
Pub.L 106-387; 114 Stat. 1549
This is known as TSRA, and was passed in 2000 and covers countries other than Cuba but sets strict regulations for trade on commodities and was heavily directed towards Cuba, particularly related to payment/payment systems for goods coming from the country. The act made the trade of certain agricultural commodities and medicine/medical devices permitted. See 66 FR 36683-01 which deals with Exports of agricultural products, medicines, and medical devices to several countries including Cuba.
Under President Barack Obama
This refers to a series of actions beginning in 2014 that were intended to change the relationship between the two counties undertaken by President Obama over the course of several years particularly in 2015 and 2016. It relates to changes to the Export Administration and Cuban Assets Control regulations. The Presidential Policy Directive issued October 14, 2016 was specifically about the framework around the normalization of relations between the two countries. By extension Treasury and Commerce Amendments lifted restrictions on Cuban cigars and rum for individuals who intend it for personal use only as well as other health, humanitarian, travel, and trade transactions.
The links below are to the archived Obama administration’s web maintained by the National Archives.
Under President Donald Trump
On June 16, 2017, the President issued a National Security Presidential Memorandum (NSPM-5) on Strengthening the Policy of the United States Toward Cuba. On November 8, 2017, the Departments of State, Commerce, and the Treasury announced certain changes to implement President Trump’s June 2017 NSPM.
Federal Register (State Department Notice, 82 FR 48875 pp.48875-48878)
Beginning in March 2019 administration has made several moves toward making it possible for U.S. citizens could sue Cuban companies that traffic in confiscated property (Title III of the Helms-Burton Act). This decision was enhanced by an announcement in April 2019 with more detailed provided by National Security Advisor John Bolton speaking at the U.S. Embassy in Cuba on April 17.
In April 2019 the administration scrapped an agreement External between Major League Baseball and the Cuban Baseball Federation that would have allowed Cuban players to sign with US teams without needing to defect.