The phrase "to become a challenge" means to present difficulties or obstacles that require problem-solving, effort and determination in order to overcome. Full definition
If two friends who are gamers themselves, they will find the games can quickly become challenges for one another. (knowtechie.com)
Writing academic assignments become a challenging task for many of the students as they need to submit high - quality assignments which will bring them with the best grades. (studentsassignmenthelp.com)
When life becomes challenging, do not fight or struggle against it. (mindbodygreen.com)