Blue/green deployment is to keep the old version, deploy the new version, then test, confirm and cut the traffic to the latest version, and then, the old version is also upgraded to the latest version.
Canary deployment is to choose to deploy a new version, introduce some traffic to the latest version, and the new and old versions provide services at the same time. Wait for the grayscale version to be OK. You can fully cover the old version. Grayscale is the coexistence of different versions, blue and green is the switch between the new and old versions, and the starting points of the two modes are different.