CSpire TV is an app provided by my cell phone provider that gives me access to local channels in MS - I can use CSpire TV app on my firestick but can not find it in the Roku Store. Is there someone else in particular that I should be looking for this app. Not sure why it showed up on my other devices but nowhere on Roku -
It would be up to your cell phone provider to create an app for Roku devices. For the most part, Roku provides the platform and third parties supply the apps. Fire TV basically runs Android apps which are nothing like Roku apps, so they may not be interested in creating an app just for Roku, but you should reach out to them to let them know you'd like one.
Each streaming platform runs on its own operating system, so each platform has to have its own unique version of the app to run on that system. These versions are created, provided to each platform the developer chooses to support, and maintained, by the channel developer.
Per this C Spire page you can download their app from the Apple App Store (for Apple devices), Google Play (for Android devices), and the Amazon App Store (for Amazon Fire devices). There is no mention of a Roku-compatible version.
Let C Spire know of your desire to have their app available for Roku.