The available/known specs for the following new products are available in the Camera Specs and Lens Specs tools on the site:
Here are a few comparisons to get you started:
Canon EOS R vs. Canon EOS 5D Mark IV
Canon EOS R vs. Canon EOS 6D Mark II
Canon RF 24-105mm f/4L USM vs. Canon EF 24-105mm f/4L IS II USM
Canon RF 28-70mm f/2L USM vs. Canon EF 24-70mm f/2.8L II USM
Canon RF 35mm f/1.8 IS STM Macro vs. Canon EF 35mm f/2 IS USM
Canon RF 50mm f/1.2L USM vs. Canon EF 50mm f/1.2L USM