Intel has detailed Thunderbolt 4, it's next-gen connectivity standard that like Thunderbolt 3 will still be based around the USB-C connector. As such, it'll be fully backwards compatible and will support various monitors, docks and storage devices. 

Thunderbolt 4 will also be fully compatible with USB 4 and both will come to Macs and PCs from the tail end of this year. These will primarily be PCs and Macs based around the upcoming Tiger Lake Intel Core processors. 

Additionally, Apple has already said that Apple Silicon Macs will support Thunderbolt just like Intel models, so it's not a leap to say that this will be Thunderbolt 4. As well as supporting Thunderbolt 4 natively in Tiger Lake, it will also make a separate Thunderbolt 4 controller, called the 8000 series. 

Again the main benefit of Thunderbolt is fast data transfer and Thunderbolt 4 boasts speeds of up to 40Gbps, so mega fast. Like USB 3/4 through USB-C, it'll be able to carry data, video and charge via the same port. 

It'll drive an 8K display or alternatively two 4K displays - a more likely scenario for many of us in the short term. Interestingly, PCs will also be able to wake from sleep when connected to a compatible Thunderbolt dock. There are also security features to prevent attacks from things plugged into the ports.