rename doesn't work with mutliindex

[pjadzinsky]

Code Sample, a copy-pastable example if possible

# Your code here
mi = pd.MultiIndex.from_product([['A','B'], [0, 1]])
df1 = pd.DataFrame(np.ones((1,4)), columns=mi)
df2 = df1.rename(columns={df1.columns[1]: ('C', 3)})
print(df1)
print(df2)

Currently both df1 and df2 are:

     A         B     
     0    1    0    1
0  1.0  1.0  1.0  1.0

Problem description

I was expecting df.columns[1] to change to ('C', 3) but it remains ('A', 1)

Expected Output

     A    C    B     
     0    3    0    1
0  1.0  1.0  1.0  1.0

[shantanu-gontia]

Can you post the expected output?

[WillAyd]

Closing as a duplicate of #4160