I believe Thanos will come back from (probably) being killed. Here is what I think will happen:
Thanos will be revived by Death to bring balance to the universe, as he/she believes that he is doing the right thing in the universe. Thanos will come back less sane then before, as he falls in love with Death and become obsessed with appeasing him/her. This will cause Thanos to be more harsh and insane, making him want to kill anyone in his way. He will find some way to bring back the infinity stones(or find some new weapon) and this time he will probably kill everyone, except for the super cosmic beings. Thanos is easily beaten by these beings, but before he is killed he is saved by death.