You can't hide a cell on its own. Hide does only work on Rows, Columns, or Sheets. Depending upon your set up, you could format it with white text so that it is invisible. Conditional Formatting could be used for this.

Other options off the top of my head are:
move it to and from a column/row that is always hidden,
put it on a separate sheet and report it on the current sheet (use an IF statement to decide whether it should be displayed or not),
put it in a text box that can be hidden or not.

Cheers, Rob.