We deduce the existence of dark matter from its gravitational attraction on other objects. Depending on what dark matter is, it may also interact very weakly with normal matter, so it may be possible to detect dark matter directly in sufficiently large and sensitive detectors. There have been several experiments attempting to do just that, but so far, with no credible results.

Existence of dark matter in space can be observed from bending of light. But it is very tough to detect dark matter particle in lab because they only interacts weakly. Lots of detectors are working to detect dark matter particles but still unsuccessful.

Although I believe on MOND and TeVeS as an alternative for dark matter, but if one can detect massive neutrinos or relics which remain from inflation and also any form of MACHOs or WIMPs we say dark energy is detected.