The parties to proceedings before the commission shall be designated as follows: a person filing a petition for review shall be called the petitioner; a person required to respond to that petition for review shall be called the respondent.
Wis. Admin. Code Tax Appeals Commission TA 1.61
Any person appealing a decision of the tax appeals commission, in addition to serving the appeal petition on each adverse party, is required by s. 227.53(1) (a), Stats., to serve the commission.