Maybe someone will come up with a cell phone case that will block all harmful radiation from the cell phone.
First, somebody would need to come up with a cellphone that emits harmful radiation. The closest they have was the old analog phones that emitted about 100X the power of modern ones.
Even then the link is iffy.
A friend of mine has one. Dunno exactly what it's made of. To test it, we were standing a couple of hundred yards from a cell tower. I had five bars. He put the phone in the pouch and told me to call him.
Nada.
Simple enough, you just need a faraday cage. A foil or knit metal mesh that has an insulator on the inside and outside so there's no physical electrical contact. The tricky part is having an opening to put the phone inside of it. A plastic zipper, for example, would provide an opening.