Не́кого presents no available person for a planned action, usually with an infinitive. Никого́ means nobody and normally forms negative concord: никого́ не вижу.
RusDrills offers 300+ free interactive Russian grammar exercises with instant feedback, spaced repetition, and audio pronunciation.
Note: This site uses JavaScript for interactive drills, audio playback, and progress tracking. Please enable JavaScript for the full experience.