try rubbing alcohol if that doesn't work put a little amount of laundry soap on it, let it sit over night then get a damp washrag and wash it off; you could also try hairspray, spray some on it, let it sit a couple minutes then wash it off with a damp washrag. if none of those work try to call a dry cleaners and ask them about it.
nail polish removerHow do I clean stainless steel appliances & remove water marks?
nail polish removal could also workremoving marker and fabric paint from walls
if its oil based ur screwed. I have used sharbies on my jeans and never came off or even smugedHow to remove large amounts of hairspray from upholstery?
I've had luck with windex. i dont know why but it works over time XDIron on patches, can you reuse them?
try nail polish remover or hairspray but its easier just to get a new backpack.
How do I remove sharpie from my bike sign on my bag
I want to advise you one way. I can not guarantee what will be displayed, but it will definitely help. Try using nail polish remover. Very carefully put it on the label and see if it goes away. I also advise you to use a steam iron and iron the inscription using it through a wet cloth. Here are some ways that can help. But you need to know what type of marker was used. You can also read useful articles on the removal of stains and the use of irons on this site It is mainly devoted to reviews on irons. But there are also many useful articles and lifehacks on its use.
Empty the backpack of its contents.
Spray enough hairspray directly onto the stain to thoroughly dampen the area.
Press down on the stain with a clean, white cloth to blot out the hairspray and ink. Continue doing this until you don't see anymore marker ink transferring to the cloth.
Dab the area with another cloth that is wet with clean water.
Blot dry again.
Dab rubbing alcohol onto the stain if any marks remain.
Blot dry once more.