If the item is currently listed you can add it to your Watch List. If it ends without selling and is relisted eBay adds a note in your Watch List "The seller relisted this item".

If the listing has already ended you could always email the seller and ask them to notify you if they are going to relist.

You could also set up a Saved Search for the item and select to receive daily emails for any new listings that match your search. To create a Saved Search, enter your search key words and any refinements and then click to Save the Search and tick the option to receive a daily email.  You can also check your Saved Searches at any time of the day through your My eBay.