DxOMark has just tested the sensor of Canon EOS R5. According to DxOMark, the sensor score for Canon EOS R5 is 95, currently highest sensor score from Canon. Canon EOS R5 currently is in stock and shipping at Amazon. You can take a look at review of Canon EOS R5 sensor for DxOMark:
As for sensor performance, the EOS R5 sensor represents a high water mark for Canon. Maximum dynamic range is competitive with the best in class, and the R5 sensor offers a useful advantage at some crucial ISO settings over its rivals. It also has excellent color and low noise at high ISOs, which all go toward making the Canon EOS R5 one of the most well-rounded performers in this important category. It may have taken a while to get here, but the Canon EOS R5 looks set to be the one to beat.