After adding the colorbar, change its position property. You can use the positions of the other axes to align the colorbar as needed.
Here's a demo (works with subplot or tiledlayout).
figure()
ax = gobjects(1,4);
ax(1) = subplot(2,2,1); title('Axis 1')
ax(2) = subplot(2,2,2); title('Axis 2')
ax(3) = subplot(2,2,3); title('Axis 3')
% add colorbar to axis 2
cb = colorbar(ax(2),'orientation','horizontal','Location','SouthOutside');
% Reposition the colorbar using the y-position of axis 3.
cb.Position(2) = ax(3).Position(2); % ax(3) is on the bottom row
