Several websites from Mexico and Latin America posted today and yesterday about Linkin Park's return to Mexico. The Mexico appearance has been rumored since the fans showed such huge interest in the band after the recent Carnivores Tour announcement.
News indicates that Beyonce, Justin Bieber and Linkin Park will play in Cancun, Mexico as part of the MTV World Stage 2014. While the band has played MTV World Stage a number of times in the past (and other LP shows have been featured on the program), the Monterrey, Mexico show in September 2012 was the last MTV World Stage event that Linkin Park participated in. Mexican authorities say "500 million people in 176 countries" will be reached via the MTV broadcast of the event.
There are several sources for the show, but here is one of the most important, "El Financiero."
Currently there is no date that has been announced and we are waiting confirmation by the band.
Update:
According to "La Verdad Noticias", a tentative date would be June / July 2014.
"The tentative dates are to be held in June or July, but it all depends on the organizers, as it is in final negotiations to bring the event."