This is a formal, written expression used when something is evaluated or decided according to a law, rule, evidence, or general principle. It is common in legal, business, or academic contexts. You can also see it in news reports. For example, a decision might be made 法律に照らして (in light of the law). It implies a careful consideration against a standard, not just a casual comparison.

Unlike similar patterns like に基づいて (based on), which focuses on following a rule, に照らして often involves checking or judging whether something complies with the standard. It can also be used with situations, as in 現状に照らして (in view of the current situation). In conversation, it sounds stiff, so use it mainly in writing or formal speeches.