The Office of Managment and Budget might seem like a less prominent position than, for example, the head of the EPA or the Department of Energy, but it's a vitally important job.

From the OMB's website:

The core mission of OMB is to serve the President of the United States in implementing his vision across the Executive Branch. OMB is the largest component of the Executive Office of the President. It reports directly to the President and helps a wide range of executive departments and agencies across the Federal Government to implement the commitments and priorities of the President.

OMB's website

The person that takes the job will have a significant impact on budgets throughout the federal government, so it's worth learning more about their views. President-elect Donald Trump's pick is Rep. Mick Mulvaney of South Carolina, and he doesn't really see the need for government-funded science research.