Returning to PIC programming after a decade...hitting a brick wall
If you follow the instructions in the PICkit 4 Getting Started Guide you will find this picture that shows the need to provide a pullup resistor on the MCLR pin of the MCU on your PC board or breadboard.



Here is where you can find the document:
https://www.microchip.com/developmenttools/ProductDetails/PG164140

Note I posted this answer primarily to provide evidence of the documentation.