One of the hallmarks of a complex living system is that there are often multiple states the system can be, and the transition between different states are often critical for biological functions. A salient example is the cell cycle, where different cellular states must be visited sequentially in order to successfully replicate itself. Evidently identifying cellular states and understanding the control mechanisms of state transitions -- in the context of specific functions – are necessary for us to reveal the inner workings of living systems. In this talk, I will highlight a few examples from my lab’s research in cancer and neuron science. I will show that the migration states of cancer cells allow them to circumvent physical barriers during metastasis, and how the transitions between migration modes are controlled by cancer cell’s physical environment. I will show neuron cells can demonstrate different communication states, and the transition between those states are controlled by temporal signals from the environment. Finally, I will overview the open questions and opportunities in my research field.