Effectively the Imperium's goals and belief system mean there will always be another conflict with humankind, they cannot stop until the entirety of sentient life is, as they say, under the 'light' of the empress. Whether this is a cultural situation playing off of their species nature or a culture shaped by the nature of life on Shil, we still don't know. However no treaty with them can be considered valid, no trade agreement honored, because in the end all means of communications and negotiation will be an avenue for shaping or arranging the situation to enable conquest and acquisition. Either slowly via economic entanglement and control or directly via long gradual planned hybrid warfare or a short term rapid and violent conquest.