Answer by taking a quote from the following article:

Mario Lanza (born Alfredo Arnold Cocozza; January 31, 1921 - October 7, 1959) was an American tenor of Italian ancestry, and an actor and Hollywood film star of the late 1940s and the 1950s. Lanza began studying to be a professional singer at the age of 16. After appearing at the Hollywood Bowl in 1947, Lanza signed a seven-year film contract with Louis B. Mayer, the head of Metro-Goldwyn-Mayer, who saw his performance and was impressed by his singing.

Lanza was the first RCA Victor Red Seal artist to win a gold disc and the first artist to sell 2 1/2 million albums  Lanza was referred to by some sources as the "new Caruso" after his "instant success" in Hollywood films, while MGM hoped he would become the movie studio's "singing Clark Gable" for his good looks and powerful voice.  In 1994, outstanding tenor Jose Carreras paid tribute to Lanza during a worldwide concert tour, saying of him, "If I'm an opera singer, it's thanks to Mario Lanza." His equally outstanding colleague Placido Domingo echoed these comments in a 2009 CBS interview with, "Lanza's passion and the way his voice sounds are what made me sing opera. I actually owe my love for opera ... to a kid from Philadelphia."  Even today "the magnitude of his contribution to popular music is still hotly debated," and because he appeared on the operatic stage only twice, many critics feel that he needed to have had more "operatic quality time" in major theaters before he could be considered a star of that art form. His films, especially The Great Caruso, influenced numerous future opera stars, including Joseph Calleja, Jose Carreras, Placido Domingo and Luciano Pavarotti. According to opera historian Clyde McCants, "Of all the Hollywood singers who performed operatic music ... the one who made the greatest impact was Mario Lanza." Hollywood gossip columnist Hedda Hopper concluded that "there had never been anyone like Mario, and I doubt whether we shall ever see his like again".

What have people said about him?
Lanza was referred to by some sources as the "new Caruso" after his "instant success"