Without the sun, most/all life would cease to exist, especially once depending on light energy from the sun like plants, forming the bases of life.
Step-by-step explanation:
Plant (producers) use light energy to photosynthesis, producing the energy or food other herbivores (plus, our primary&secondary consumers) dependant upon, to survive; then, they get preyed upon (by our tertiary consumers) - structuring the food chain as we all know of. Hence, sustaining life/ living organisms on earth, for generations to come.
Thus, all life on earth as we know it, basically, won't exist. Abiotic factors are the one's to live a happy ever after. There are non-living, once that don't undergo cellular respiration like us humans, e.g., rocks don't respire.
Anyways the sun is a star, one day (millions to billions years onwards) it's predicted to engulf our earth, when transitioning to become a red giant. So, it might not sustain earth forever.
Don't panic, you won't live to experience this! How fantastic does this sounds?
Hope this helps!