Halo Infinite's campaign missions aren't replayable, but the issue is being 'worked on' according to developer 343 Industries.
Halo Infinite has plenty of collectibles to vacuum up but the inability to replay some missions means that, if you miss collectibles in certain areas the first time around, you won't be able to go back and pick them up later. That's because Halo Infinite doesn't allow you to replay missions within the same save file. To replay missions you need to start a new save file
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