Normally we read many things about the best scenarios and advantages for this type of approach. However I would like to hear your opinion regarding the disadvantages and risks regarding the implementation of Continuous Integration and Delivery, mainly about the risks, strategies and if there are technologies (ColdFusion, PHP...for instance) which this approach cannot be implemented or it would be more difficult.
Interesting question you propose here. Since you are asking my opinion I will say that using Continuous Integration / Continuous Delivery is much more of a risk than not using CI/CD methodologies.
I say this for a couple of reasons:
Manually processes such as running test suites in a local machine versus in a clean CI build can be problematic. You might have certain environment variables set in your local machine, a work of art that only is properly configured in your machine.
Working on a team of any size you want an independent machine that can have declarative steps on how to be configured and what environment variables to set and jobs to kick off. If you were to try to do this outside of CI/CD methodologies you run the risk of missing a step in a manual process. CI/CD really ties in with the concept of automation and you can have multiple builds that serve in the Deployment Pipeline. The more automation you have in place along with CI/CD processes you can economies of scale in delivering a quality product to your customers/end users.
It is not that manual processes are evil but just that they are not repeatable and reproducible like automated processes are.
You can certainly use PHP in Travis CI and other CI/CD products, I believe that Jenkins has a plugin for Cold Fusion that you can use not totally sure on that but all in all CI/CD is a very important process.