According to TV Line, "the proposed reboot is not moving forward at this time after failing to attract a suitor." This, of course, sounds like Warner Bros. was unable to entice any networks into picking up the series, which first premiered on NBC in 1986.
Co-created by Paul Fusco, who also voiced and served as the puppeteer for the titular character, ALF followed Alien Life Form Gordon Shumway in his refuge with a middle-class suburban family in America after crash-landing on Earth following his home planet's destruction. The sitcom ran from four seasons between 1986 and 1990, with Fusco reprising the iconic role in commercials and guest appearances in the 28 years since the series' cancellation.
Following a television movie in 1996, Fusco pitched a feature film adaptation of ALF to Sony Animation, with the project expected to be a blend of live-action and CGI. While Sony optioned the project in 2012, it has since been abandoned.
Of course, there's always the chance a network could express interest in reviving ALF. In the meantime, though, the nostalgiac alien icon will remain just that: nostalgiac.