In this post and also in your previous post you are asking about the differnce between the Past Simple (He came) and the Present Perfect (He has come). The difference is that in the first sentence you are referring to an isolated action in the past without referring to its relation to the present, while in the second sentence you are showing how a past action has influenced the present. Therefore if you say 'He came', at the moment of speaking he might have left once again or he could have remained there, we do not know.
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