Apple Security Engineering and Architecture (SEAR), User Privacy, Core Operating Systems (Core OS), Services Engineering (ASE), and Machine Learning and AI (AIML):

Alongside the next generation of Apple Intelligence, today we’re expanding Private Cloud Compute (PCC) beyond Apple’s data centers. 

[…]

What’s new with PCC on Google Cloud is the implementation: NVIDIA Confidential Computing with NVIDIA GPUs, Intel CPUs with TDX, and Google’s Titan chip. On this foundation, Apple and Google collaborated to build capabilities that go far beyond a traditional confidential computing deployment.