Short answers, pulled from the story.
Kevin Feige announced the Marvel Cinematic Universe Phase Three film slate on the 28th of October 2014 at the El Capitan Theatre in Hollywood. This event marked the first time Marvel Studios held a solo presentation for its film lineup without waiting for another convention.
The initial announcement of the Marvel Cinematic Universe Phase Three included Captain America: Civil War, Doctor Strange, Guardians of the Galaxy Vol. 2, Thor: Ragnarok, Black Panther, and Captain Marvel alongside two Avengers crossovers. The studio later added Ant-Man and the Wasp to the phase after Spider-Man joined the franchise.
Anthony and Joe Russo directed Captain America: Civil War, Infinity War, and Endgame while collaborating closely with other directors across the phase. They worked with James Gunn on Guardians of the Galaxy Vol. 2 and Taika Waititi on Thor: Ragnarok to ensure narrative continuity.
Phase Three became the highest-grossing phase more than doubling Phase Two's $5.3 billion gross at the worldwide box office. The total gross for the phase ranged from $2.294 billion to $2.403 billion across all releases.
Avengers Endgame dethroned Avatar on the 21st of July 2019 becoming the highest-grossing film at the time unadjusted for inflation. This achievement occurred during a year when three MCU films made at least $1 billion each including Captain Marvel, Endgame, and Spider-Man Far From Home.