Imagine a magical piece of hardware that no one can see inside, even if they break it open, that is the promise of Intel SGX and TEEs (Trusted Execution Environments).
Cryptographers for decades have been pushing the limits of secure computation. This is when the computing party is oblivious to the result and underlying data. Example: did Alice or Bob supply a larger number without revealing the underlying numbers to training machine learning models on encrypted data. Some of these problems have been solved, but often times the solutions are neither generalised nor efficient.