https://wccftech.com/apple-silicon-mac-pro-to-use-m1-max-variant/

Apple’s transition to using custom silicon is expected to be stretched to its most powerful workstation, the Mac Pro. In the past, we have reported that compared to the current model that is fueled by an Intel chip, the upcoming one will be half the size of the cheese grater. However, it might not feature a chipset that is made from scratch, with a new report claiming that it might be a variation of the M1 Max found in the 2021 MacBook Pro family.

It is not uncommon for Apple to use the same chipset for a variety of products, with a few changes here and there. After all, we should think of the M1 Pro as just another variation of the M1 Max but with a smaller die size. Similarly, one variant that could be found in the upcoming Mac Pro may tout an even bigger die size, allowing Apple to add more CPU and GPU cores, not to mention to the ability to incorporate a higher amount of unified RAM.