An RF Safe article argues that plasma membrane potential (Vm) is a key control variable for immune cell behavior by shaping ion driving forces, especially Ca2+ influx through CRAC channels and K+ channel–mediated hyperpolarization. It describes proposed links between Vm-regulated ion flux and downstream immune functions such as T-cell activation (NFAT/NF-κB signaling), macrophage polarization, respiratory burst capacity, and NLRP3 inflammasome activation. The piece also mentions that external electric fields can influence T-cell migration and activation markers under some conditions, but it does not present new experimental data in the excerpt provided.