Generally, telescopic opamp Input CM range is too small to cover telescopic opamp Output Signal range (including CM+DM components)。Once output signal range exceed telescopic opamp Input CM range,the performance (eg. gain/bandwith) of telescopic opamp will degrade.
However, in case that the input signal is a DC voltage level and within the Input CM range of telescopic opamp, the input and output terminals of telescopic opamp can be connected directlty to configure a non-inverting gain (=1) amplifier/buffer.