Modifications such as transcranial direct current stimulation or Elon Musk's neural lace type designs for reading are leaving the realm of science fiction and raising questions about whether the modern (trans)human requires rights around cognitive liberty, mental privacy and integrity, and psychological continuity.
Theoretical attacks on consumer-grade brainwave sensing headsets have been designed that could steal thoughts like security PINs should one switch between a banking app and a specially configured malicious game.
In fictional universes featuring mind uploading or cyborgization (e.g. Altered Carbon, Ghost in the Shell), all kinds of nefarious memory erasures, modifications, remote control and influences are featured. Today access to your computer may be for sale by criminals, tomorrow will it be your mind?
Is your mind your intellectual property? Because you may run into all sort of problems. Copyable minds open up new exponential risks such as economic impacts featured in the Age of Em and personal duplication featured in Ghost in the Shell and Black Mirror.
If your body is replaceable, what opportunities for fraud and impersonation does this open up?
Virtual reality looks like a convenient place - to torture you. :/
Where immortality or externally-apparent immortality is featured via backups and the like (Altered Carbon, Commonwealth Saga), the threat of backup contamination or destruction is sometimes wielded by evil-dooers. Backups may cost extra.