Is not getting treatment for a disease considered as suicide in Islam?

I had this question for many years and still don't know if it is suicide or not, in one way you { by not taking the "cure" which is chemotherapy, and others } wish yourself death. but I don't think it is a suicide, because, in the end, Allah will decide for me to live or die. please be free to refer to any hadith or aya that mention this subject.