According to a report from Bloomberg, Apple is presently working on higher-end chips for its Mac computers, most notably the MacBook Pro and iMac variants. Sources familiar with the subject disclosed to the outlet that the company’s engineers are working on 20 core CPUs, with up to 16 high-performance cores and 4 low power cores.
However, for time being the team is only aiming to design 8-12 core chips, and as per the reception, plan to follow through with higher-core models depending on yields. Keep in mind that like Intel, Apple also makes monolithic chips with all the cores on the same die.

While this does improve latency, it’s much more expensive and wastage is notably higher. You can read more about the differences between the two in the above article.
Apple is planning to test designs with core counts as high as 32 cores by 2022. Considering the low-yields, it’s possible that we’re looking at a multi-chip module (MCM) or chiplet approach similar to AMD’s.
On the graphics side, Apple presently offers 7-8 core GPUs with its M1 processors which are quite paltry compared to what most mobile PCs come with. You can expect 16 and 32 core GPUs with the next-gen Apple parts and possibly as many as 64 to 128 cores later on (if all goes well).

Apple’s Arm chips may be very impressive compared to its rivals in the mobile market, but the PC market is very different. AMD already has 16 core mainstream desktop parts and 64 core Threadrippers for the HEDT space.
Apple’s M1 processor has an IPC roughly on par with AMD’s Zen 2 core and a fair bit lower than the newer Zen 3 and Intel’s Willow Cove design. AMD is expected to launch the Zen 4 based processors based on the 5nm node which will bring another 15-20% IPC boost and allow an increase in core count of up to 32 for the maintream PC market and up to 96 cores in the HEDT space. It’ll be interesting to see how Apple’s plans pan out.