Sanji and Zoro are in the same crew called Straw Hat Pirates. They are always fighting over something and anything, a rival, but that doesn't mean Sanji hates Zoro. He cares about Zoro

One day, at Thriller Bark island, they got attacked by Kuma and Zoro sacrificed himself for Luffy and his crew. Sanji is there with him but Zoro knocks him out. When Sanji finally awakes again, he immediately goes to find Zoro who is just standing there with arms crossed over his chest and blood all over his body and ground. Sanji's eyes widen in shock and he is worried but Zoro said nothing.

Zoro lost a lot of blood and on the verge of death, now is laying on the bed with his body covered in bandages, still not waking up while everyone else celebrates their victory. They don't know Zoro's sacrifices except Sanji and Robin