Either side in a criminal case may appeal with respect to the sentence that is being imposed.
People convicted at trial may have the right to appeal the decision to a federal court of appeals. Not all cases are accepted for appeal, but those that are will move on to this higher court. In criminal cases specifically, a defendant who is found to be guilty may want to appeal the verdict if the case was impacted by errors, possible juror misconduct, or various other unfair practices.
The Appeals Process
Determine whether or not you can appeal
Collect the record of papers and documents filed in the trial court
File a notice of appeal with the court
Determine whether an appeal bond must be filed to delay the execution of a sentence
The appellant team files memorandum and writes briefs
Appellee has the right to respond / file a counter-memorandum