In short, tourism is a part of travel, but not all travel is tourism. When a person travels for tourism, he or she is traveling for leisure. This will entail a different mindset. This means that the people in the destination will also have a different mindset.
Travel, on the other hand, is broad. People can travel for many reasons. For example, a person can travel for business to a remote region to start a mining company. If he or she does that, there might be nothing there, certainly no industries for tourism.