Let's break it down.
Disney (the studio affiliated with Marvel) wants to split the cost of financing the next Spider-Man film 50/50 with Sony.
Turns out Sony weren't too pleased with that siggestion, and have insisted they stick to their agreed upon split from their 2015 deal.
If Sony were to agree to the 50/50 co-financing split, they would be giving up half of their biggest franchise.
So where does Tom Holland come in?
Sony has made it clear they plan on making two more Spider-Man movies with or without Disney. Tom and Zendaya are affiliated strongly with Marvel Studios, so if the deal falls through, Sony will be sure to eradicate any semblance of Marvel - including Tom and Zendaya!
Let's pray these Disney and Sony don't ruin a good thing!