Final answer:
After leaving Warner Bros., Harman and Ising started MGM's animation department and created new cartoon series, including Barney Bear, and they were initially involved in the production of Tom and Jerry.
Step-by-step explanation:
After leaving Warner Bros., Harman and Ising went on to work for Metro-Goldwyn-Mayer (MGM). They were instrumental in starting the animation department there in 1934, following their departure from Warner Bros. The duo was known for their work on the early versions of Looney Tunes and Merry Melodies series. At MGM, they created a new series of cartoons, including the popular character Barney Bear. However, the most success they found at MGM was with the creation of the Tom and Jerry series, which was initially produced by their team but later helmed by William Hanna and Joseph Barbera.