The docker run -p 3000:5000 command maps port 3000 on the host to port 5000 on the Docker container. This means that any process on the host that wants to access the service running inside the container should connect to port 3000 on the host. The service inside the container listens on port 5000, but from the host's perspective, it will be accessed via port 3000. More information on Docker port mapping can be found in the Docker documentation.