In my experience the traditional branching strategies work for monorepos for continuous integration.
For continuous deployment the circumstance is a little different since you may not want continuously deploy every app if there are changes that don't affect all apps.
For example, supposing a monorepo that contains source for three separate apps A, B, C. If a branch contains changes for app A only, when merged, you may not want to redeploy all apps, but only affected apps. In this case you may want to organize a conditional deployment model instead of a continuous model. If you CICD system is tied to branches, and branch events, you may need to organize a separate release branch modeling along side the preexisting integration model.
