Xavier Amatriain's answer to How do I combine more than one recommender algorithms? - Quora

I won't go into details of how to do this, but in a few words all you need to do is to train your independent models and then use their predictions as features of another ML model that puts them together. This ensemble layer can be as simple as a logistic regression or as complex as a deep Neural Network, but given your question I would definitely encourage you to start with the simplest model possible.