The career roadway after Data Science depends largely on the interests of the individual. Post becoming an expert in the field of Data Science, if the individual yearns to seek a career in management & business strategy; then he may shift roles and use his/her experience of business problem solving to devise optimal strategies for the business.
Alternately, if the individual wishes to go deep into the world of technology; the next level is known as ‘scientific computing’ which tends to model the underlying process rather than simply the data to predict outcomes (which is the case with data science & machine learning).