Know the differences between Iteration and Release planning and how testers add a value in it.

Release planning is process to plan the deployment of the product you develop during your sprints in the production environment. Remember the environment in which you test the system can be quite different from the actual production environment. Your test environment might not have third party integrations whereas your production environment would have. As a tester you can raise risks around release deployments and actually own them as well along with the release manager. It is never easy to build a production like environment. However, you can foresee things, you can exactly tell where the things can fall during release deployment based on your sprints testing experience.
Some companies however struggle to automate release deployment .There are plenty of tools available for continuous deployment in the market these days.
One of the projects I was working on we were using Bamboo deployment plugin to deploy latest build code in different environments.
In Jenkins there are some nice plugins like delivery pipeline plugin and pipeline plugin that can be used to manage and monitor deployments in various environments.
Some companies are using Ansible for deployment using containers. Unlike virtual machines, containers run on Linux machines. One machine can have 100s containers and each container can run a micro service in it.
Ansible is one of the best took to manage these containers it seems.
As a tester you can upskill your self on these tools and improve the Release planning and deployment process of your project.