* "In the slang" This phrase is incorrect. Slang is a style of language, not a container.
* "What's in slang?" This could mean:
* "What is the slang word for...?" For example, "What's the slang for 'money'?"
* "What's in this slang phrase?" This would ask for the meaning of a specific slang expression.
* "What's 'in' slang?" This could be asking for current slang terms, like "What are the latest slang words?"
To give you a more specific answer, please clarify your question. For example:
* What are you trying to find out? (The meaning of a word, a specific slang phrase, or just popular slang in general?)
* Can you give me an example of what you're looking for?
Once I understand your question better, I can help you!