If they both work for the same organization to achieve common goal, communicate through some interface they agree on, having to coordinate occasional changes th

If they both work for the same organization to achieve common goal, communicate through some interface they agree on, having to coordinate occasional changes that affect both codebases, than no. If they are completely isolated, than yes, but its really rare scenario. A common example would be a website that gathers/presents some data from users, and a service that provides analytics of said data. Both domains may require completely different technologies.