The company has had a tumultuous year. LinkedIn shares crashed as much as ~27% after disappointing Q1 earnings in April.
Icahn is famous for buying into companies and then being extremely vocal about his suggestions for how the company can improve or return cash to shareholders through stock buybacks and dividends.
Of course, these are just rumours, for now. On multiple occasions, Wall Street whispered that Icahn would buy into Twitter, which he never has.