Lead is part of the news that is a sentence that contains 5w1h and the main point of the whole news, also consist of 25-35 word. From the lead, the reader may have an idea of what the news is about even when they are not read the news completely. However, the lead should be made as interesting as possible and has to grab the reader's attention, also makes the reader want to read the news.
Intro is a sentence that becomes the beginning part of the news, also contains fewer elements of 5w1h.
Example:
A five-year-old Indian boy, who was separated from his conjoined twin in 2017, has died. (Lead)
Jaga and Kalia, who were conjoined at the top of their heads, underwent several major surgeries when they were two years old. (Intro)
Source:
https://www.bbc.com/news/world-asia-india-55082404