Infracost has introduced a new "infracost diff" command inspired by "git diff" to compare monthly cloud cost estimates for Terraform projects between their current and planned states. This tool highlights differences in cloud costs by identifying changes in various components, such as AWS EC2 instances and their associated resources like EBS block devices, which can impact costs significantly. It provides detailed insights, such as the effect of reducing the size of a Provisioned IOPS SSD Storage, which can save substantial costs annually, although implementing such changes may not be straightforward. Additionally, for new resources like AWS Lambda functions, the tool can display cost structures based on usage, allowing users to input usage estimates through a YAML file to better predict expenses. The "infracost diff" command supports CI/CD integrations, is open-source, and encourages community feedback through GitHub and Slack.