You may trust an email from your boss and it may look legitimate but it can be a big scam. According to Web Root, a cyber security firm, this is the phishing scam that most people fall for.
It is an email that looks like it's coming from your boss, but it has been spoofed. Someone has made up that email, they are trying to get you to send sensitive company or account information; something that could scam you or your company.
So if you get a suspicious email like this, make sure you pick up the phone, call your boss and verify.