The France captain drew a blank in warm-up games against Ivory Coast and Northern Ireland and ended the season at Real Madrid without a trophy, despite finishing as La Liga's top scorer.
His performances, leadership and behaviour away from the pitch have become regular talking points after Real Madrid fell short in both the Champions League and the domestic title race.
Mbappe has also come under fire over his leadership since succeeding Hugo Lloris as captain in 2023, with 1998 World Cup winner Frank Leboeuf among those to question whether he is the right man to lead Les Bleus.
Yet inside the France camp, support for Mbappe appears unwavering.
Ballon d'Or winner Ousmane Dembele, who has emerged as one of the team's most influential figures, said the criticism directed at his long-time teammate and close friend had gone too far.
"The criticism towards him is very, very unfair," Dembele told Spanish newspaper Marca this week.
"Some people overdo the criticism because he's Kylian Mbappe. They shouldn't keep going after him. Whether he ties his shoelaces or not, whether he pulls up his socks or not, it's too much. He's still a human being.
"With the France team, he's very good with us, he's a leader."
Defender Lucas Hernandez struck a similar tone, saying Mbappe remained fully focused despite the noise around him.
"When you're Kylian Mbappe, everyone looks at everything you do, on the pitch and off the pitch," Hernandez said.
"He's 100% motivated for the World Cup. All the criticism there has been this season, he's going to silence it."
France are among the favourites to lift the trophy and Didier Deschamps is embarking on his final tournament in charge, giving Mbappe an immediate opportunity to turn the conversation back to what he does best.
If there is one stage on which Mbappe rarely disappoints, it is the World Cup, where France will also face Iraq and Norway in Group I.
He has struck 12 times in 14 World Cup matches, leaving him only four goals short of Miroslav Klose's all-time record of 16 and offering a reminder of how quickly he can silence his critics.
Another goal would put him top of the list of France's all-time scorers alongside the retired Olivier Giroud (57).