It means that they are all people with very rich experience, and no one should try to deceive anyone.
This line comes from Cai Ming's skit "Dance if you want to" at the 2013 CCTV Spring Festival Gala, in which she played a retired old lady, and it was one of her classic lines.
The original line reads, "They're all thousand-year-old foxes, what kind of chit chat are you playing with me?" Said to Captain (Ms.) Zhao of the dance team, fighting for the bullied old man played by Pan Changjiang.
Expanded:
According to the general interpretation, a fox that has become fertilized can also be called a fox fairy, which is more beautiful, but a fox that has become fertilized is called a fox spirit, which contains a derogatory meaning. Thousands of years fox spirit Taoism is profound. But are a thousand years, indicating that since they are all the same that no one should deceive anyone.