Idioms: in a string of

If something is the latest in a line/string/series of something, it is the most recent in a series.

"Single Ladies" is the latest in a string of pop hits by Beyoncé.

He is the latest in a line of great company presidents.

The bombing was the latest in a series of attacks across the country.

This is often used when talking about news events.

If you say something is the "latest", the series might not have finished. For example, in the examples above, perhaps Beyonce will have more pop hits; perhaps there will be more great company presidents.

The last in a series means the series has finished.

"The Long and Winding Road" was the last in a long series of number 1 hits by the Beatles.

In Islam, Mohammed was the last in a line of the prophets of God.