Marco wants to know if he can trust getting links from friends on the iPhone. Leo says that if his friends send him links over a PC, he'd be worried. But over the iPhone, it's completely safe.
Mark has an iPhone 6 Plus, and he clicked on a link in his email from "Fedex" which he later realized was a bogus phishing scam. Leo says it's unlikely it'll impact Mark. Phishing scams are designed mostly at Windows applications and even then, unpatched versions of Windows. Since Mark is neither, it's highly unlikely anything bad will happen to his phone. But it's good that he realized it, even if it was too late. Next time he'll know beforehand.