Mary Tyler Moore made enormous strides in what women were permitted to do on TV. First, on the Dick Van Dyke show, she insisted on wearing pants, but the sponsors hated the idea so much they limited it to one scene per show. Still the first woman that wore pants in a sitcom.
Then, for the Mary Tyler Moore show, she was the first single working woman in a sitcom. They initially wanted to make her divorced, but network execs wouldn't let it fly, famously saying that the only things that worked less for TV than a working woman were divorces, Jews, and men with mustaches...each of which the show eventually featured