Надо breakpoint поставить.

Мой launch.json и task.json
{
"version": "0.2.0",
"configurations": [
{
"name": ".NET Core Launch (console)",
"type": "coreclr",
"request": "launch",
"preLaunchTask": "build",
"program": "${workspaceFolder}/bin/Debug/net5.0/Demo.dll",
"args": [],
"cwd": "${workspaceFolder}",
"console": "internalConsole",
"stopAtEntry": false
}
]
}
{
"version": "2.0.0",
"tasks": [
{
"label": "build",
"command": "dotnet",
"type": "shell",
"args": [
"build",
// Ask dotnet build to generate full paths for file names.
"/property:GenerateFullPaths=true",
// Do not generate summary otherwise it leads to duplicate errors in Problems panel
"/consoleloggerparameters:NoSummary"
],
"group": "build",
"presentation": {
"reveal": "silent"
},
"problemMatcher": "$msCompile"
}
]
}