I'm dreading the possibility of Thanos being used as a one-shot jobber villain to put Ikaris over in the second issue of the new Eternals comic, like how he was used by Bendis in Civil War II and GOTG.
I don't think Ikaris alone should be able to beat Thanos in a duel. Ikaris is barely above oldschool green Hulk's level (maybe i'm wrong, i don't remember his feats well) while Thanks was able to beat Superman level characters like Silver Surfer, Thor, Beta Ray Bill and the Fallen One (Samaritan) and made Pre-Aaron Odin (Blood & Thunder) and Tyrant (Cosmic Powers) struggle a bit.