Não
De "Vantagem e Desvantagem" (PHB p.173):
When you have advantage or disadvantage and something in the game, such as the halfling’s Lucky trait, lets you reroll the d20, you can reroll only one of the dice. You choose which one.
Os lutadores recebem a habilidade Indomável no nível 9.
Beginning at 9th level, you can reroll a saving throw that you fail.
Se o Fighter falhar em um teste de resistência feito com o Advantage e usar o Indomitable para tentar novamente, o novo rolo também é feito com o Advantage?
De "Vantagem e Desvantagem" (PHB p.173):
When you have advantage or disadvantage and something in the game, such as the halfling’s Lucky trait, lets you reroll the d20, you can reroll only one of the dice. You choose which one.