Ok, I've come across this just now so I thought I'd share, take it with a grain of salt though since I'm not sure of the author's track record, he did find out and report about DL1 getting delayed before it actually happened back in the day, so make of that what you will.
source: https://graczpospolita.pl/zapowiedz-dying-light-2/
Here's translation of the most important bit from the article:
"I've managed to determine by a few independent sources, as well as both current and ex Techland employees, that the company is working on Dying Light 2.
Currently the studio is focused on preparing a high quality trailer, which is going to be presented during upcoming E3 in Los Angeles [12-14 June]. When asked if due to the release of standalone DLC Dying Light: Bad Blood, which focuses on multiplayer battle royale gameplay, there was a chance to expand on it in Dying Light 2, the answer was "it's highly probable". Bad Blood is supposed to be a first major test for such a mode in the world of Dying Light. I've also received a confirmation the the announcement of DL2 was constantly being put off because the first game was still receiving support and the team was focused on aforementioned Bad Blood addon. Seems quite reasonable."
Also worth noting, Techland is working on another big project and it's not Hellraid, which supposedly "was definitively deleted/cancelled". No details on what it is though, at least not yet.
Jak udało mi się ustalić w kilku niezależnych źródłach, także wśród byłych i obecnych pracowników Techlandu, firma pracuje nad Dying Light 2.
Obecnie studio skupia się na przygotowaniu wysokiej jakości trailera, który ma być zaprezentowany podczas zbliżających się targów E3 w Los Angeles (12-14 czerwca). Na pytanie, czy w związku z premierą samodzielnego dodatku Dying Light: Bad Blood, który skupia się na rozgrywce wieloosobowej w stylu battle royale, jest szansa na rozwinięcie go w Dying Light 2 usłyszałem, że "jest to bardzo prawdopodobne". Bad Blood ma być pierwszym prawdziwym testem dla tego trybu w świecie DL. Dostałem też potwierdzenie, że zwlekano z zapowiedzią, gdyż nadal wspierana jest pierwsza część Dying Light oraz zespół skupia się na wspomnianym Bad Blood. Brzmi całkowicie logicznie.
source: https://graczpospolita.pl/zapowiedz-dying-light-2/
Here's translation of the most important bit from the article:
"I've managed to determine by a few independent sources, as well as both current and ex Techland employees, that the company is working on Dying Light 2.
Currently the studio is focused on preparing a high quality trailer, which is going to be presented during upcoming E3 in Los Angeles [12-14 June]. When asked if due to the release of standalone DLC Dying Light: Bad Blood, which focuses on multiplayer battle royale gameplay, there was a chance to expand on it in Dying Light 2, the answer was "it's highly probable". Bad Blood is supposed to be a first major test for such a mode in the world of Dying Light. I've also received a confirmation the the announcement of DL2 was constantly being put off because the first game was still receiving support and the team was focused on aforementioned Bad Blood addon. Seems quite reasonable."
Also worth noting, Techland is working on another big project and it's not Hellraid, which supposedly "was definitively deleted/cancelled". No details on what it is though, at least not yet.