Answer:
Tradition is called a cultural or social practice that remains in use for several generations, generating a rootedness with the society in which it develops. This society, then, adopts these practices as its own and adopts them as elements of its identity.
In turn, contemporary is called everything that takes place in the present time, being any activity or practice that takes place during the course of current time.
Thus, when a tradition becomes so ingrained in society that it remains in force during the present, the traditional becomes contemporary and current. The clear example is the Halloween festivities, which began as a cultural tradition and today are a contemporary event. In turn, the contemporary can also become traditional, if it achieves sufficient roots to be so.