[2] On 8 May 2015, he was also included to form part of the final roster that will participate in the 2015 FIFA U-20 World Cup.

[3] In Mexico's third group match against Serbia, Lainez played the last 35 minutes in the team's 2–0 loss.

Lainez was called up by Jaime Lozano to participate with the under-23 team at the 2019 Pan American Games,[4] with Mexico winning the third-place match.

[5] In September 2020, Lainez received his first senior national team call-up by Gerardo Martino for a training camp.

[6] Lainez received his second call-up to the senior national team, and made his debut on 8 December 2021 in a friendly match against Chile, coming in as a substitute in the 83rd minute for Sebastián Córdova.