It could just be the biggest year in movie history as 2019 has some mega blockbusters slated to premiere. While there are plenty of great standalone films debuting in 2019 like Captain Marvel (March 8), The Lion King (July 19), and Sonic the Hedgehog (November 8), many of the biggest films of the year sequels.
Easily the biggest movie of 2019 and of the last 10 years could be Avengers: Endgame (April 26). It should have the largest worldwide gross of the year. It's the fourth in line of the Avengers flicks and the 22nd in the Marvel Cinematic Universe timeline. Avengers: Infinity War earned over $2 billion in 2018, according to Box Office Mojo, with its sequel set to match, if not surpass, it.
Star Wars: Episode IX (December 20) will give Avengers: Endgame a run for its money, likely having a bigger domestic gross, but may not be able to top it worldwide. From 2015-2017, a Star Wars film was number one in the box office every year. Since the MCU has been building up to Endgame over the last 10 years, it could surpass Episode IX since each Star Wars movie has declined in numbers since The Force Awakens in 2015.