The best way to defrost sliced cheese so that the sliced cheese keeps it's texture is to slowly defrost the sliced cheese.
The way you can defrost the sliced cheese slowly is to remove it from the freezer 24 hours prior to using the cheese.
Then place the sliced cheese into the refrigerator and allow the sliced cheese to slowly thaw out in the refrigerator for 24 hours.
Then after 24 hours the sliced cheese should be fully thawed out to eat.
You can also place the frozen sliced cheese in a bag such as Ziploc bag and then place it in hot water and the hot water will thaw it out.