From
lichess.org/page/appeal:
>What does appealing do?
>When you appeal a decision that has been made by a Lichess moderator or by one of our automated moderation processes, it will >be reviewed by a different moderator. There are no automated elements in the decision review process. Human moderator(s) >assess all the relevant evidence that informed the original decision before deciding whether it was justified or not, and informing >you of the final outcome.
Basically, if you think that your ban is unjustified, you may request for it to be looked over again by a more senior moderator.
From
lichess.org/page/report-faq:
>What happens to my report?
>[...] This process might take a day or two.
