From Wikipedia:
What's My Line? is a weekly panel game show, which originally ran in the United States from 1950 to 1967 with several international versions and subsequent U.S. revivals. The game tasked celebrity panelists with questioning contestants in order to determine their occupations. It is the longest-running game show in the history of prime time network television. Hosted by John Charles Daly and with panelists Dorothy Kilgallen, Arlene Francis and Bennett Cerf, What's My Line? won three Emmy Awards for "Best Quiz or Audience Participation Show," in 1952, 1953 and 1958 and Golden Globe for Best TV Show in 1962.
In 1968 it returned in syndication as a daily production which ran until 1975. There have been several international versions, radio versions, and a live stage version.
Produced by Mark Goodson and Bill Todman for CBS television, the show was initially called Occupation Unknown. The original series, which was usually broadcast live, debuted on Thursday February 2, 1950 at 8:00 p.m. ET. After airing alternate Wednesdays, then alternate Thursdays, finally on October 1, 1950 it had settled into its weekly Sunday 10:30 p.m. ET slot where it would remain until the end of its network run on September 3, 1967.