Tamara ate two fifths of the candy bar, and Amir also ate two fifths of the candy bar.
To find out how much of the candy bar they ate in total, we can add the two fractions:
\[ \frac{2}{5} + \frac{2}{5} = \frac{4}{5} \]
This means that together they ate four fifths of the candy bar.
Now, to find out how much is left, we subtract the amount they ate from the whole candy bar:
\[ 1 - \frac{4}{5} = \frac{1}{5} \]
Therefore, the amount of the candy bar that is left is \(\frac{1}{5}\).