Per Interfax news, the governor of the Sakhalin Region Valery Limarenko says a fixed link to Sakhalin island is again on the agenda. But in the form of a railway bridge instead of a tunnel. In 2018, Putin had asked his cabinet to investigate the options for the fixed link to the Sakhalin Island which lies 6,5 off shore of mainland.

With planned 580km long single track railway line, it is reported that such a bridge would cost 300 Billion rubles with another 300 Billion rubles for the approaches.

https://www.interfax.ru/russia/953974