Canon has been the global leader in camera market share for a couple of decades now, and that has continued through 2020, and Canon's market share actually grew over 2019 according to the latest numbers by Nikkei (paywalled).
The bad news is that the global camera market shrunk by 40% in 2020, mainly due to the COVID-19 pandemic, but 2021 should see an increase in the total number of cameras sold, but I don't think it'll recover from that 40% drop in one calendar year.
The two cameras that had a big part in increasing Canon's market share are likely the EOS R5 and EOS R6 which Canon has said repeatedly have blown past sales expectations. The EOS M50 series of cameras are also still big sellers for Canon.
Digital camera market share in 2020 by manufacturer
- Canon 47.9% (+2.5%)
- Sony 22.1% (+1.9%)
- Nikon 13.7% (-4.9%)
- Fujifilm 5.6% (-0.3%)
- Panasonic 4.4% (-0.3%)
I expect Canon's market share to grow further once new and more affordable camera bodies are brought to market in 2022. The Canon EOS R3 likely won't move the needle, but the replacements for the EOS RP and EOS R will drive higher volume sales for Canon. More affordable options are coming, but with the challenges that still exist in manufacturing, higher volume cameras will likely be held off until those issues are resolved.