A spokesman for Canon confirmed the development of a new camera that can record video in 8K resolution. It will be full frame and mirrorless. Along with this device, the company is working on a less expensive EOS R family camera and another model for professional use, but it will not appear soon.
Resource The Verge notes that Canon is sometimes blamed for the lack of development of support for 4K resolution. For example, 5D Mark IV and 1D x Mark II with 4K were released in 2016, but these are mirror models.
As for mirrorless cameras, the EOS M50 camera with 4K support appeared only last year. The new EOS R, of course, also works with 4K, but due to technical features (Crop Factor 1.8), a survey of general plans is not easy.
The timing of the appearance of a mirrorless full-frame camera with shooting 8K video is not yet called.