For congress, they have been willingly ceding power to the executive for most of US history. The most obvious one is war making and war declarations. Congress will cede powers that are risky or divisive between donors and constituents or factions of either. They mostly just want to hang on to enough power to get the lobbying dollars and get sinecure jobs afterwards, but not enough power that they make risky decisions that would piss off those donors/corporations.
For congress, they have been willingly ceding power to the executive for most of US history. The most obvious one is war making and war declarations. Congress will cede powers that are risky or divisive between donors and constituents or factions of either. They mostly just want to hang on to enough power to get the lobbying dollars and get sinecure jobs afterwards, but not enough power that they make risky decisions that would piss off those donors/corporations.