What is GitLab CI/CD?
GitLab CI/CD is the part of GitLab that you use for all of the continuous methods (Continuous Integration, Delivery, and Deployment). With GitLab CI/CD, you can test, build, and publish your code with no third-party application or integration needed.
Read more about GitLab CI/CD here.
GitLab CI/CD
What is GitLab managed terraform state?
GitLab provides a built in Terraform state feature, so instead of keeping the terraform state file in the local system or repository, you can store the state file in GitLab and can be referenced while performing various terraform operation using GitLab pipeline.
The terraform file terraform.tfstate stores the state of your infrastructure provisioned on the cloud platform by terraform, and if you lose it means that Terraform would not know the status of your current infrastructure on the cloud platform. This file can be stored to a remote Git repo for sharing, but it is not a good practice because the state file could easily get out of sync if it is not handled carefully.