From dankwiki

100 Gigabit Ethernet achieves 100Gbs data rates using the Ethernet Layer 2 protocol over a variety of media, usually using QSFP28 transceivers. There are four generations, depending on whether it's 10x10Gb, 4x25Gb, 2x50Gb, or pure 100Gb per direction. It is defined on CAT-7A and CAT-8 copper, twinaxial, and fibre.

100GbE NICs

PCIe 3.0 at 8 lanes doesn't have sufficient throughput to carry a full 100Gbps; its theoretical max is 7.877GB/s or 63.016Gb/s. PCIe 4.0 at 8 lanes or PCIe 3.0 at 16 lanes are necessary. A full 200Gbps signal (or two 100Gbps ports) requires 16 lanes of PCIe 4.0 or 8 lanes of PCIe 5.0. A full 400Gbps signal (or two 200Gbps ports) requires 16 lanes of PCIe 5.0, 8 lanes of PCIe 6.0, or 4 lanes of PCIe 7.0.