CBS had a slew of hits in the early 70s, including a wartime comedy called M*A*S*H.  CBS went to the wartime well again in 1973 with this comedy about a battalion of primarily African-American soldiers in France during World War II.  As bad as the ratings were, that may not have been what got the show cancelled so quickly.  It's not good when your lead and a supporting cast member were arrested during the show's brief run.