Is 委员会 a commission or a committee? According to Xinhua News Agency, China Daily and other official media outlets of English language of China, 中央纪律检查委员会 is Central Commission for Discipline Inspection, but 中央政法委员会 is Committee of Polictical and Legal Affairs,发展和改革委员会 is National Development and Reform Commission,中央直属机关工作委员会 is Work Committee for Departments Directly Under the CPC Central Committee.

Commission and committee are both used to mean 委员会, what is the difference?
A commission is a group appointed by the government to accomplish a certain task. The commission can cease to exist when the task is completed (e.g., the 9/11 Commission, which investigated the events surrounding 9/11). Or the commission can be ongoing indefinitely (e.g., the Securities and Exchange Commission, which oversees Wall Street).

In government, committee is a group of people who meet to make a certain decision or to gather information and produce documents. Committees, too, can be short-lived or long-term.

A committee can also be a commission, and vice-versa. Because the term "commission" is more specific than "committee," a group of people that fit both descriptions would usually call themselves a commission. For example, when a crisis affects a city or state, the mayor or governor will usually appoint a commission to gather information, make decisions/recommendations, and accomplish certain other tasks.

Sources:

https://painintheenglish.com/case/3801

https://www.quora.com/What-is-the-difference-between-commission-committee-and-council