I'm not sure what you are asking. "It's lead to sth else "means? doesn't make any sense. Are you trying to write: "It leads to something else." You should also say in what context the statement is made and I can help you.

It means that one action may lead to another. Perhaps, the worry that too much kissing will lead to behaving too intimately. A common idiom is 'one thing leads to another.' Example: A sale at the department store leads to (causes there to be) larger crowds.

'sth' often stands for 'something' but it is a shortcut that I don't recommend using outside of texting and social media.