Who was the first person to do a spacewalk?
Soviet/Russian cosmonaut Alexei Leonov (1934 – 2019) was the first person to go an a spacewalk. The technical term for spacewalk is "EVA" (Extra Vehicular Activity).
On 18 March 1965, while on the Soviet Voskhod 2 mission, Alexei Arkhipovich Leonov performed the world's first EVA. He was outside the spacecraft for 12 minutes and 9 seconds. While outside, his spacesuit expanded to the point that it would not fit back through the door into the capsule. Facing an unpleasant death, Leonov was able to open a valve and let some air out of his spacesuit and deflate it enough to fit through the door.
Leonov was later selected to be the first Soviet person to land on the Moon, however the project was cancelled. In July 1975, Leonov commanded the Soyuz half of the Soyuz–Apollo mission, the historic first Soviet/USA cooperative space mission.