Interdependent co-arising pratityasamutpada is one of the key teachings of the Buddha & is commonly called Dependent Origination so what's it about?
It's sometimes thought of as the teaching of cause & effect, which as human beings, we're prone to interpret as seperate things - cause always preceding effect and a continuation thereafter in a linear way, but it's not so simple.
One such teaching which we commonly see is that of the 12 nidanas or 12 linked chain of causation from the 5th century Theravada Buddhist monk Buddhaghosa, detailing the cycle of becoming, birth, decay and death arising from unrecognised greed, hate and delusion (the push/pulls and doubt, fear & confusion).
Implicit within Dependent Origination is the teaching of anicca or Impermanence meaning everything changes and nothing remains the same in any consecutive moment as well as the teaching of anatta, that nothing can exist by itself alone. It has to depend on every other thing.
As an example, if we see a flower we are also seeing a multitude of causes - we are seeing the flower's parents and the process of reproduction, the seed, the right temperature & amount of sunlight dependent on the right distance between the Earth & the Sun, rain & it's causes, the correct balance of carbon dioxide, oxygen & nitrogen and a type of soil which is able to sustain the flower's growth. As well as it's causes, the process we call a flower also has potential to reproduce, produce oxygen, decay, co-create soil and make us smile - but only in conjunction with myriad other factors.
Each thing is reliant and dependent on seemingly infinite others, without end or beginning, which is why we might say they are inter-dependent and what we perceive are in fact co-arising processes rather than things at all.
The Buddha summed it up this way: 'This is, because that is. This is not, because that is not. This comes to be, because that comes to be. This ceases to be, because that ceases to be.' More simply, Thich Nhat Hanh said 'This is like this, because that is like that'.