some people; several people; a few people
Used to refer to an unspecified small number of people, often in contrast to a larger group or when the exact number is unknown or unimportant.
There were some people I knew at the party.
Several people raised their hands.
何人 asks 'how many people?' as a question, while 何人か statement means 'some/several people' with an unspecified number.
Combination of 何人 (how many people) and the particle か, which turns the interrogative into an indefinite expression meaning 'some' or 'several'.