https://www.cdc.gov/mmwr/volumes/69/wr/mm6928e2.htm
> Among 139 clients exposed to two symptomatic hair stylists with confirmed COVID-19 while both the stylists and the clients wore face masks, no symptomatic secondary cases were reported; among 67 clients tested for SARS-CoV-2, all test results were negative. Adherence to the community’s and company’s face-covering policy likely mitigated spread of SARS-CoV-2.
Stanford Medicine's assessment[2] states that, "Although there were also fewer COVID-19 cases in villages with cloth masks as compared to control villages, the difference was not statistically significant."
[0] https://www.poverty-action.org/study/impact-mask-distributio...
[1] https://www.webmd.com/lung/news/20210907/masks-limit-covid-s...
[2] https://med.stanford.edu/news/all-news/2021/09/surgical-mask...
One big issue was that the mask pickup didn't equally reduce cases across ages. This leads to the training for wearing masks may have caused older groups to stop socializing, rather than the masks doing anything.