How has the introduction of eSIMs affected Digital Forensics and what challenges do they bring?

I'm looking for some pointers to help me get started with the below questions. 

1) How has the introduction of eSIMs affected Digital Forensics?

2) What challenges do eSIMs bring?

I'm not after the answer per say, I just need pointing in the right direction for any literature, media or key terms/words that might help

Thank you