A shorter and more concise answer
import pyodbc
import pandas as pd
cnxn = pyodbc.connect(r'DRIVER={Microsoft Access Driver (*.mdb, *.accdb)};'
r'DBQ=C:\users\bartogre\desktop\data.mdb;')
sql = "Select sum(CYTM), sum(PYTM), BRAND From data Group By BRAND"
data = pd.read_sql(sql,cnxn) # without parameters [non-prepared statement]
# with a prepared statement, use list/tuple/dictionary of parameters depending on DB
#data = pd.read_sql(sql=sql, con=cnxn, params=query_params)