Pandas copy() different columns from different dataframes to a new dataframe
You are overwriting df3.
Method-1:
   import pandas as pd

    df1 = pd.read_csv('ASX_public_DB.csv', sep=';', skiprows=5)
    df2 = pd.read_excel('ASX_delisted_6months.xlsx')

    df3 = df1[['ticker_symbol']].copy()
    df3['ASX code'] = df2[['ASX code']].copy()

    print(df3)

Method-2:
    import pandas as pd

    df1 = pd.read_csv('ASX_public_DB.csv', sep=';', skiprows=5)
    df2 = pd.read_excel('ASX_delisted_6months.xlsx')

    df3 = pd.DataFrame()
    df3['ticker_symbol'] = df1['ticker_symbol'].copy()
    df3['ASX code'] = df2['ASX code'].copy()

    print(df3)
```