Searching directly on Wikipedia, you can find that the English of "two sessions" is Lianghui. AFP, Reuters, The Wall Street Journal and other media translated the two sessions into "two sessions". The People's Daily used this translation, and the BBC also translated the "two sessions" in a recent report.

the National People's Congress

National People's Congress (NPC)

Nature: the highest organ of state power

Chinese People's Political Consultative Conference

China People's Political Consultative Conference (CPCC)