caching is not a function of the model but the provider, all models can be cached. the provider serving the model decides if they are going to cache it. openrouter is not a provider but a middleman between providers, so some of their providers for deepseek might provide caching and some might not. if you just use any then you might run into the issue. some of their provider might use your data for training, some might not. you have to look at the list and you can cherry pick ones that won't train on your data and that also provide caching.