The appeals court found his claims to be ridiculous. They ruled unanimously that he did not have immunity. Just like any other citizen, he is responsible for illegal behavior. Being president does not put him (or anyone else) above the law.
The appeals court gave Trump two weeks to appeal their decision to the Supreme Court. If the Supreme Court justices are smart, they will refuse to accept the case. The Constitution does not guarantee any president the right to break the law with impunity.
Trump had claimed that a president could not act without immunity -- that the other party would charge a president for actions they didn't like while he was president. That's a silly argument. All the presidents preceding Trump had not problem acting while obeying the law, and there is no reason to think that won't remain true in the future.
The United States has presidents -- not dictators. And this ruling insures that will remain true.