A hive mind in its original form is a form of emergent intelligence most especially associated with social insects (e.g., ants, bees, and termites), where collective behavioural patterns emerge which are independent of, and not fully explained by, any individual behaviours or intelligence. The term is of course also applied to humans, perhaps most famously as "the madness of crowds", as popularised by the book of the same title.

Groupthink, to skip over cargo cults for a moment, is a case where individual beliefs and/or behaviours are influenced by a group, often as an otherwise poorly-substantiated set of beliefs or actions, usually in agreement with some leader. Why groupthink emerges and what possible social/psychological evolutionary advantages it might convey (compensating for the cost of beliefs at odds with reality and empirical evidence) are hotly debated. Unlike the hive mind, groupthink isn't emergent, in the sense that individuals express specific beliefs or exhibit specific behaviours, though generally associated with the group context.

Cargo-cults are a form of groupthink. My own view is that cargo cults emerge in response to highly complex phenomena, either entirely beyond the grasp of individuals, or pushing the limits of scientific or technical knowledge. The original form, emerging on Pacific islands during and following WWII were a case of a non-technological culture (the native island inhabitants) trying to attain the benefits of a technological society (the various military belligerants of WWII) by emulating airstrips and the hope of the cargo (goods and services) these apparently brought the advanced society. Air-borne transport is knowable by humans, but only in a given social-technological context, which the islanders lacked.

In other instances, cargo culting tends to resemble fads and fashions where indicia or characteristics of some complex concept are adhered to, sometimes to achieve their ends, sometimes to indicate adherence to or alignment with a group. Fashion, language, dress, management trends, and software development practices (3GL, structured code, Agile, ML, and the like may all be examples in at least some cases). Often the foundations are more than purely technical, e.g., management or investors may feel a need to follow the crowd / leaders, often to avoid scapegoating or accountability in the event of failure.

All of which of course is distinct from the false-competence delusion of an expert within one domain presuming expertise in others, e.g., Nobel Disease <https://en.wikipedia.org/wiki/Nobel_disease>.