Terraform and CloudFormation are both declarative tools (although you can make either tool work imperatively through depends_on and wait conditions). And CloudFormation will give you a sneak preview of what’s going to change through its change set feature while Terraform can generate a plan file and execute that plan. Both of these tools’ “change set” features can be used in automation/pipelines.

AWS CloudFormation also has a drift detection feature that is handy in shops where maybe your Infrastructure-as-Code guys run amok with the console from time to time :)