What is the difference between STO and ICO?

Excuse me, could you please explain the distinction between an STO and an ICO? As I understand, both involve raising funds through the issuance of digital tokens, but I'm not entirely clear on the key differences between the two. Specifically, I'm interested in knowing how they differ in terms of regulatory compliance, investment risks, and the types of investors they typically attract. Additionally, could you also elaborate on the potential benefits and drawbacks of each approach? Thank you in advance for your insights.