As far as I know, there isn't a widely known movie that features Channing Tatum and a dog specifically based on a true story. Channing Tatum has been in many movies, but this combination doesn't ring a bell in terms of a true - story - based film. However, it's possible that there could be some independent or less - known projects out there that might fit this description.
There might not be a movie that directly matches this description. Channing Tatum is known for his diverse roles in movies. While dogs are common in films, having a movie that is specifically about a dog and has Channing Tatum and is based on a true story is not something that comes to mind immediately. It could be that this is a very niche or upcoming project that hasn't gained much mainstream attention yet.