According to a recent leak, it seems the first three entries will receive native PS5 ports.

Life is Strange Remastered, Life is Strange: Before the Storm Remastered, and Life is Strange 2 Complete Season have all been rated by the ESRB for the PS5. Although the PS4 versions of these games are playable on the current-gen PlayStation console, these will be native ports for the PS5, which means they could potentially take advantage of the improved bells and whistles of the console.