You can use lerp or a tween node.
Lerp
camera.translation = lerp(start_point, end_point, lerp_amount)
#camera.position for 2D
lerp_amount += speed
Tween
tween.interpolate_property(camera, "position" or "translation", start_point, end_point, speed, Tween.TRANS_LINEAR, Tween.EASE_IN_OUT)
tween.start()