Is it safe to leave perishable food in a cooler inside a hot car?

No, it’s not safe for several hours. A cooler is insulation, not refrigeration, and in a car that can hit 130°F+, the internal temp will climb above 40°F, letting bacteria grow. If you must, use a high-quality rotomolded cooler with pre-chilled contents and ice packs, but don’t trust it past two hours for perishables.