[leave] {sb} out in the cold

to exclude or neglect someone, often intentionally, from a group or activity

The idiom "leave someone out in the cold" is believed to have its origins in the harsh realities of winter weather. In cold climates, being left outside without shelter or warmth can be extremely uncomfortable and even life-threatening. This literal scenario of isolation and exposure to the cold evolved into a figurative expression used to describe situations where individuals are excluded or neglected, often intentionally, leaving them feeling isolated, unsupported, or uninformed, much like being left out in the frigid cold.

During the important company meeting, the manager left several team members out in the cold by not sharing crucial information.
When it came to organizing the surprise party, they deliberately left their nosy friend out in the cold to maintain the element of surprise.
The new employee felt left out in the cold when her coworkers formed close-knit groups and excluded her from social gatherings.
The team leader's decision to make key decisions without consulting the team left everyone feeling out in the cold and disconnected from the project.
The company's sudden restructuring left many employees out in the cold, unsure about their roles and job security.