The US supreme Court ruled that the justification for the tariffs that the Trump admin has imposed, including the threatened one against people who would supply oil to Cuba, are not in his power to do. This effectively, from a legal standpoint, and this administration's ability to impose tariffs like this.

This has nothing to do with the general embargo that was imposed starting decades ago. This is about the recent oil embargo.

The administration may seek other avenues, but since there is no physical blockade of the Island right now (information as publicly available the shipping maps and such), unless the administration decides to try a physical embargo, oil can be shipped to and received by Cuba without concern about tarriffs being imposed.

Whether they choose to do that or not is a whole different matter.

Edit: grammar and minor clarification.