Intel's 12th gen Alder Lake-S Core processors are rumoured to be Intel's first 10nm-class mainstream desktop processors - and documentation, data sheets and release notes for these CPUs has already appeared on the Intel developer site. Unfortunately, the linked data is locked unless you are an Intel employee but on the linked page you will see associated datasheet for Socket LGA1700.
According to current Intel nomenclature, LGA1700 will host 500 more pins than present on the latest LGA1200 form factor, used to support 10th Gen Core chips for mainstream desktop (14nm Comet Lake). That is a big increase and it is expected that the Alder Lake-S CPUs will be quite sizable products (more business for the cooler market). Extra pins might be used for greater power delivery, new feature support, or expanded I/O capabilities - or all these things.
This bigger socket, and larger package size, will give Intel some room to grow its multi-chip module offerings. Alder Lake-S could be Intel's first consumer processor generation to support up to 16 physical cores. A significant part of the package might be set aside for the Xe iGPU too. In Alder Lake's case we are expecting to see the arrival of Intel's hybrid CPU designs on the desktop. Thus the 16 cores might be 8 big and 8 LITTLE cores. The recently detailed Lakefield mobile CPUs feature Sunny Cove and Tremont doing big/LITTLE lifting, but Alder Lake-S this is likely to be configured as Golden Cove (Willow Cove successor) and Gracemont (Tremont successor).
Intergenerational comparison chart via Japan's G-PC.info
Other rumoured important technologies for the Intel 600 Series chipset for Alder Lake-S are; the PCIe 4.0 interface standard (probably arrives with 11th gen Rocket Lake-S), and DDR5 memory support.