Can 120v and 277v be in the same conduit?

No you can not mix voltages. That being said if the lower voltage is part of the control circuit from a MCC control centre then yes they can be mixed as the low voltage control is part of the complete system.

Composite power & control Teck 90 cable has the power feeders and usually 3/#12 or 3/#14 wires embedded in the same cable. These three wires allow for remote stop - start controls to be mounted neat the motor out in the field.